  United States Court of Appeals
      for the Federal Circuit
               __________________________

  CHICAGO BOARD OPTIONS EXCHANGE, INC.,
           Plaintiff-Cross Appellant,
                            v.
INTERNATIONAL SECURITIES EXCHANGE, LLC,
           Defendant-Appellant.
               __________________________

                    2011-1267, -1298
               __________________________

   Appeal from the United States District Court for the
Northern District of Illinois in Consolidated Case Nos.
07-CV-0623 and 07-CV-4709, Judge Joan H. Lefkow.
             ___________________________

                  Decided: May 7, 2012
              ___________________________

   DAVID FRANCESCANI, Fish & Richardson P.C., of New
York, New York, argued for plaintiff-cross appellant.
With him on the brief were JONATHAN A. MARSHALL,
MICHAEL T. ZOPPO, BRIAN J. DOYLE and LINZY
MCCARTNEY.

    PARKER H. BAGLEY, Goodwin Procter, LLP, of New
York, New York, argued for defendant-appellant. Of
counsel on the brief were STEVEN R. GUSTAVSON, MICHAEL
S. DE VINCENZO, CALVIN E. WINGFIELD, JR. and CHARLES
WIZENFELD. Of counsel was BENJAMIN A. KELLER.




    * Honorable Jeremy Fogel, District Judge for the
United States District Court for the Northern District of
California, sitting by designation.
CHICAGO BOARD   v. INTL SECURITIES                         2


                 ________________________

Before RADER, Chief Judge, WALLACH, Circuit Judge, and
               FOGEL, District Judge.*
WALLACH, Circuit Judge.
    International Securities Exchange, LLC (“ISE”) ap-
peals from a final judgment entered by the United States
District Court for the Northern District of Illinois, holding
that the trading system of Chicago Board Options Ex-
change, Inc. (“CBOE”) does not infringe ISE’s United
States Patent No. 6,618,707 (“the ’707 Patent”). CBOE
cross-appeals the district court’s denial of its motions for
leave to amend its Complaint. Because the district court
erred in construing “system memory means,” “matching,”
and “automated exchange,” and did not abuse its discre-
tion in denying CBOE’s motions for leave to amend its
Complaint, we AFFIRM-IN-PART, REVERSE-IN-PART,
VACATE-IN-PART, and REMAND.
                       BACKGROUND
     The ’707 Patent, titled “Automated Exchange for
Trading Derivative Securities,” discloses an invention
that relates generally to markets for the exchange of
securities. ’707 Patent, col.1 ll.13-14. In particular, the
’707 Patent is directed to an automated exchange for the
trading of options contracts that allocates trades among
market professionals and that assures liquidity. Id. col.1
ll.14-17. The Patent distinguishes an “automated” ex-
change from the traditional, floor-based “open-outcry”
system for trading options contracts. Id. col.1 ll.24-26.
    In an open-outcry system, trading takes place through
oral communications between market professionals at a
central location in open view of other market profession-
als. Id. col.1 ll.27-29. For example, an order is typically
3                          CHICAGO BOARD   v. INTL SECURITIES


relayed out to a trader standing in a “pit.” Id. col.1 ll.29-
30. The trader shouts out that he has received an order
and waits until another trader or traders shouts back a
two-sided market (the prices at which they are willing to
buy and sell a particular option contract), then a trade
results. Id. col.1 ll.30-34.
    The ’707 Patent builds on this traditional exchange
system. Specifically, the Patent purports that “[i]t is an
advantage of the invention to provide an automated
system for matching previously entered orders and quota-
tions with incoming orders and quotations on an exchange
for securities, which will improve liquidity and assure the
fair handling of orders.” Id. col.4 ll.55-59. Figure 2 of the
’707 Patent illustrates the exchange in detail:
CHICAGO BOARD   v. INTL SECURITIES                          4




The data interface 23 performs error checking, data
compression, encryption, and mediates the exchange of
data between the exchange and public customers, profes-
sionals, and other entities. Id. col.8 ll.56-60; Fig. 2. Order
and quotation information received via the interface 23 is
sent to the order process 25. ’707 Patent, col.8 ll.64-66.
The order process 25 first checks to see if the order or
quotation is valid according to programmable parameters
that reflect the particular trading rules of the entity
administering the invention. Id. col.8 l.66-col.9 l.2. Order
process 25 also checks, among other things, whether a
fast market condition (i.e., high market volatility) exists,
whether the order is a public customer or professional
5                              CHICAGO BOARD   v. INTL SECURITIES


order, and what prices are in the away markets. See
generally id. col.9. Under certain conditions, upon deter-
mining that a better price does not exist in an away
market, order process 25 sends orders to the bid matching
process 34 (offers to buy) and to the offer matching proc-
ess 36 (offers to sell). Id. col.9 ll.58-64. Accordingly,
representative claim 1 recites, in part:
    1. An automated exchange for trading a financial
    instrument wherein the trade may be one of a
    purchase of a quantity of the instrument and a
    sale of a quantity of the instrument, the exchange
    comprising:
        an interface . . .
        book memory means . . .
        system memory means for storing allocat-
        ing parameters for allocating trades be-
        tween the incoming order or quotation and
        the previously received orders and quota-
        tions; and
        processor means . . . .
Id. col.29 l.53-col.30 l.15.
    CBOE operates the Chicago Board Options Exchange
using the Hybrid Trading System (the “Hybrid”), which
allegedly infringes the ’707 Patent. The Hybrid inte-
grates a version of CBOEdirect, a fully screen-based
trading system, with open-outcry trading. CBOE has
described the Hybrid as an integrated single market
system that blends the elements of open-outcry and
electronic execution.
    ISE instituted the underlying lawsuit against CBOE
for patent infringement in the United States District
Court for the Southern District of New York. Subse-
CHICAGO BOARD   v. INTL SECURITIES                        6


quently, CBOE sued ISE at the United States District
Court for the Northern District of Illinois seeking, among
other relief, a declaratory judgment that the ’707 Patent
is invalid, is not infringed by CBOE, and is unenforceable
against CBOE because of inequitable conduct by ISE
before the United States Patent and Trademark Office.
The New York action eventually was transferred to the
Northern District of Illinois where the cases were consoli-
dated.
    On January 25, 2010, the district court issued its final
claim construction order. On April 15, 2010, CBOE moved
for summary judgment of noninfringement based on the
district court’s construction of the terms “system memory
means,” “matching,” and “automated exchange.” On
March 2, 2011, the district court denied CBOE’s motion to
the extent that motion was based upon the “automated
exchange” limitation, but granted the motion with respect
to “system memory means” and “matching.” ISE appeals
the district court’s claim construction of the three limita-
tions and the resulting summary judgment decision.
Prior to CBOE’s motion for summary judgment, the
district court twice denied CBOE’s motion for leave to
amend its Complaint, denials that CBOE now cross-
appeals. We have jurisdiction over both appeals pursuant
to 28 U.S.C. § 1295(a)(1).
                        DISCUSSION
     ISE raises three issues on appeal: (1) whether the dis-
trict court erred in construing “system memory means”
and further erred in granting summary judgment of
noninfringement with respect to claims 1-6, 9-10, and 22-
33 of the ’707 Patent based on its construction of “system
memory means”; (2) whether the district court erred in
construing “matching” and further erred in granting
summary judgment of noninfringement with respect to
7                         CHICAGO BOARD   v. INTL SECURITIES


claims 35, 36, 43, 45, and 56-58 of the ’707 Patent based
on its construction of “matching”; and (3) whether the
district court erred in construing “automated exchange.”
By its cross-appeal, CBOE raises the issue of whether the
district court abused its discretion in denying CBOE leave
to amend the inequitable conduct allegations in its Com-
plaint.
                             I.
    We review a district court’s claim construction de
novo. Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448,
1454-55 (Fed. Cir. 1998) (en banc). Likewise, “[a] district
court’s identification of the function and corresponding
structure of a means-plus-function limitation is . . . re-
viewed de novo.” JVW Enters., Inc. v. Interact Accessories,
Inc., 424 F.3d 1324, 1329 (Fed. Cir. 2005) (citation omit-
ted). To ascertain the scope and meaning of the asserted
claims, we look to the words of the claims themselves, the
specification, the prosecution history, and, if necessary,
any relevant extrinsic evidence. Phillips v. AWH Corp.,
415 F.3d 1303, 1315-17 (Fed. Cir. 2005) (en banc).
                            A.
     The district court erred in holding that the corre-
sponding structure for “system memory means” included a
system memory, a bid matching process, and an offer
matching process. Claim 1, representative of the asserted
apparatus claims, recites, in pertinent part: “An auto-
mated exchange for trading a financial instrument . . . ,
the exchange comprising: . . . system memory means for
storing allocating parameters for allocating trades be-
tween the incoming order or quotation and the previously
received orders and quotations . . . .” ’707 Patent, col.29
ll.53-56, col.30 ll.1-4 (emphasis added). The district court
construed “system memory means” to be a means-plus-
function limitation and construed its function to be “stor-
CHICAGO BOARD   v. INTL SECURITIES                        8


ing parameters of the entity administering the invention
for allocating trades between the incoming order or quota-
tion and the previously received orders and quotations.”
Joint Appendix (“J.A. __”) 34. The district court also held
that the corresponding structure includes three separate
components: a system memory; a bid matching process;
and an offer matching process. Id.
    The parties’ dispute lies in the district court’s con-
struction of the limitation’s corresponding structure.
Specifically, ISE argues that the district court erred in
holding that the bid matching process and the offer
matching process are necessarily included as structure of
“system memory means” along with a system memory.
ISE also avers that sufficient structure is disclosed in the
claim language itself to overcome the presumption of a
means-plus-function limitation. CBOE contends that the
district court did not err in including the bid matching
process and the offer matching process as part of the
structure of a “system memory means” because the stor-
ing of allocating parameters for professional orders occurs
in the system memory and the storing of allocating pa-
rameters for public customer orders occurs in the bid
matching and offer matching processes.
    As an initial matter, ISE’s contention that the recita-
tion of “system memory” is sufficient structure to over-
come the presumption of a means-plus-function limitation
was not before the district court. The parties expressly
agreed during claim construction that “system memory
means” is a means-plus-function limitation. J.A. 11. ISE
may not take a different position on appeal. See Lazare
Kaplan Int’l, Inc. v. Photoscribe Techs., Inc., 628 F.3d
1359, 1376 (Fed. Cir. 2010) (“As we have repeatedly
explained, litigants waive their right to present new claim
construction disputes if they are raised for the first time
9                          CHICAGO BOARD   v. INTL SECURITIES


after trial.”) (citation and quotation omitted). 1 We there-
fore turn to the district court’s interpretation of the corre-
sponding structure for “system memory means,” which we
treat as a mean-plus-function limitation.
   Means-plus-function limitations are governed by 35
U.S.C. § 112, ¶ 6, which provides:
    An element in a claim for a combination may be
    expressed as a means or step for performing a
    specified function without the recital of structure .
    . . in support thereof, and such claim shall be con-
    strued to cover the corresponding structure . . .
    described in the specification and equivalents
    thereof.
As such, § 112, ¶ 6 “represents a quid pro quo by permit-
ting inventors to use a generic means expression for a
claim limitation provided that the specification indicates
what structure(s) constitute(s) the means.” Atmel Corp. v.



    1   Even if this argument was not waived, the pre-
sumption that “system memory means” is a means-plus-
function limitation is not overcome. Specifically, the
claim language fails to sufficiently recite the correspond-
ing structure of “system memory means.” In particular,
the limitation articulates a function, but nowhere in the
language of the limitation is there a specific and definite
structure of a “system memory means.” As a result, this
limitation as drafted does not aid a skilled artisan in
ascertaining its corresponding structure because no such
structure is sufficiently recited. See Serrano v. Telular
Corp., 111 F.3d 1578, 1582 (Fed. Cir. 1997) (“The ‘deter-
mination means’ limitation . . . recites a means for deter-
mining the last digit without reciting definite structure in
support of that function, and that limitation therefore is a
‘means plus function’ limitation . . . .”). Accordingly,
“system memory means . . .” is a means-plus-function
limitation.
CHICAGO BOARD   v. INTL SECURITIES                       10


Info. Storage Devices, Inc., 198 F.3d 1374, 1381 (Fed. Cir.
1999).
    Construction of a means-plus-function limitation in-
volves two steps. First, the court must identify the
claimed function. Applied Med. Res. Corp. v. U.S. Surgi-
cal Corp., 448 F.3d 1324, 1332 (Fed. Cir. 2006). Second,
the court must identify the corresponding structure in the
specification that performs the recited function. Id. The
parties’ dispute in this case concerns only the second step.
     It is well-established that the “specification must be
read as a whole to determine the structure capable of
performing the claimed function.” Budde v. Harley-
Davidson, Inc., 250 F.3d 1369, 1379 (Fed. Cir. 2001). A
“structure disclosed in the specification is corresponding
structure only if the specification or prosecution history
clearly links or associates that structure to the function
recited in the claim.” Med. Instrumentation & Diagnos-
tics Corp. v. Elekta AB, 344 F.3d 1205, 1210 (Fed. Cir.
2003) (citation omitted). “The duty of a patentee to
clearly link or associate structure with the claimed func-
tion is the quid pro quo for allowing the patentee to
express the claim in terms of function under section 112,
paragraph 6.” Id. at 1211 (citations omitted). Thus, “[i]f
an applicant fails to set forth an adequate disclosure, the
applicant has in effect failed to particularly point out and
distinctly claim the invention . . . .” Biomedino, LLC v.
Waters Techs. Corp., 490 F.3d 946, 948 (Fed. Cir. 2007)
(citation omitted). Whether the specification “adequately
sets forth structure corresponding to the claimed function
necessitates consideration of that disclosure from the
viewpoint of one skilled in the art.” Budde, 250 F.3d at
1376.
    In this case, system memory is the disclosed structure
clearly associated with “system memory means.” CBOE
11                         CHICAGO BOARD   v. INTL SECURITIES


attempts to draw a fine line with a broad brush by con-
tending that the system memory alone does not store
allocating parameters for both public customer and pro-
fessional orders as the claims require. Based on this
premise, CBOE argues that the bid and offer matching
processes must be included as structure of a “system
memory means” because the bid and offer matching
processes store allocating parameters pertaining to public
customer orders while the system memory stores allocat-
ing parameters related to professional orders. The speci-
fication, however, tells a different tale as system memory
indeed is linked with storing allocating parameters for
both types of orders.
    For example, certain parameters for determining
whether an incoming public customer order is automati-
cally traded are, in fact, stored in the system memory:
     The derive or trade process 32 will either . . .
     automatically match an incoming public customer
     order that improves the market for fewer than 10
     contract at the order’s stated price, or else derive
     an order for the [Professional] at the stated price
     at the order so that the size of the best price will
     be 10 contracts. Whether an order is automati-
     cally traded or whether an order is derived is de-
     termined by a parameter stored in the system
     memory 26.
’707 Patent, col.22 ll.32-39 (emphases added). Likewise,
the Patent describes a set of predetermined parameters
stored in the system memory that pertain to public cus-
tomer orders that are either traded or stored based on
away market prices:
     The away market process 28 either trades the
     public customer order automatically against the
     [Professional] at the same price as the better price
CHICAGO BOARD   v. INTL SECURITIES                         12


   in the away market 17 or else stores the order in
   the book memory 33 and alerts the [Professional]
   to the order according to a set of predetermined
   parameters stored in the system memory 26 by the
   [Professional].
Id. col.9 ll.46-51 (emphases added). 2 In yet another
example, fast market parameters are stored in the system
memory that introduce time delays and determine opti-
mal price for executions based upon orders and quotes
that accumulate during the delay. Id. col.9 ll.14-22.
Because optimal price is determined based on orders and
quotes that accumulate during the delay, the parameters
stored in the system memory necessarily pertain to all
orders, including public and professional orders. 3


       2    Professional” refers to Primary Market Mak-
ers (“PMMs”), Competitive Market Makers (“CMMs”), or
Electronic Market Makers (“EAMs”) as articulated in the
Patent. See ’707 Patent, col.6 l.62-col.7 l.11.
    3    The prosecution history of the ’707 Patent further
confirms that the patentee contemplated and desired to
clarify that the system memory, in fact, stored allocating
parameters for both professional and public customer
orders:

    Claims 1 and 35, as filed, recite the identification
    of customer and professional orders and the use
    of a stored parameter to allocate portions of an
    incoming order among previously received orders.
    Thus, as discussed below, claims 1 and 35, as
    well as the claims which depend from them, prior
    to the present amendment, are submitted as pat-
    entable over the prior art. Nonetheless, to more
    clearly show that parameters stored in the system
    memory are used to allocate portions of an incom-
    ing order or quotation, amended claims 1 and 35
    recite this as an “allocating” parameter.
13                        CHICAGO BOARD   v. INTL SECURITIES


    Despite this language in the specification, CBOE con-
tends that the bid matching process and the offer match-
ing process “store” allocation parameters because they
“apply” and “contain” allocation parameters. In effect,
CBOE argues that “store,” “apply,” and “contain” have
similar meanings. See Bid for Position, LLC v. AOL, LLC,
601 F.3d 1311, 1317-18 (Fed. Cir. 2010) (holding “bid” and
“value of the bid” to have the same meaning because the
claim language and specification used the terms inter-
changeably). We disagree.
    The term “store” or a derivation thereof is associated
with “system memory” or “book memory” or a “memory”
every time the term is used in the specification. Nowhere
is “system memory” or “book memory” associated with
“apply” or “contain.” Nothing in the Patent suggests that
“storing” and “applying” are used interchangeably in
reference to allocating parameters.        Hence, CBOE’s
contention that the bid matching process and the offer
matching process “store” allocating parameters fails
because the Patent does not ascribe the same meaning for
“apply,” “contain,” and “store.” The general presumption
that different terms have different meanings remains. See
CAE Screenplates, Inc. v. Heinrich Fiedler GmbH & Co.
KG, 224 F.3d 1308, 1317 (Fed. Cir. 2000) (“In the absence
of any evidence to the contrary, we must presume that the
use of these different terms in the claims connotes differ-
ent meanings.”). Accordingly, we construe the function of
“system memory means” to be “storing parameters of the
entity administering the invention for allocating trades
between the incoming order or quotation and the previ-
ously received orders and quotations.” The clearly linked



Response to Office Action dated November 2, 1999 at 29
(emphases added), J.A. 2130.
CHICAGO BOARD   v. INTL SECURITIES                      14


structure associated with this function is “system mem-
ory.”
                             B.
    The district court concluded that “matching” and “al-
locating” are distinct processes, and we agree. However,
the district court erred by concluding that “matching”
may be based on price only. Claims 35 and 56 are repre-
sentative of the asserted method claims. Claim 35 recites:
   35. A process for trading a financial instrument
   on an automated exchange wherein the trade may
   be one of a purchase of a quantity of the instru-
   ment and a sale of a quantity of the instrument,
   the process comprising:
   ...
         first matching a first portion of the incom-
         ing order or quotation against the public
         customer order stored in the book memory
         based on the allocating parameter; and
         second matching a remaining portion of
         the incoming order or quotation preferen-
         tially against professional orders and quo-
         tations with larger size based on the
         allocating parameter.
’707 Patent, col.35 ll.23-26, 40-47 (emphases added). In
addition, claim 56 states, in part: “matching the incoming
order or quotation against the orders and quotations
stored in the book memory based on the allocating pa-
rameter . . . .” Id. col.39 ll.18-20 (emphases added).
    The district court construed “matching” to mean
“identifying a counterpart order or quotation for an in-
coming order or quotation based on price.” J.A. 32. It also
construed “allocating” to mean “dividing all or portions of
15                        CHICAGO BOARD   v. INTL SECURITIES


the incoming order or quotation among the previously
received orders and quotations.” J.A. 31. It construed
“allocating parameters” as “rules for dividing portions of
the incoming order or quotation among the previously
received orders and quotations,” and determined that
allocating and matching are distinct processes. J.A. 29,
32.
     ISE contends that the district court’s construction
limiting “matching” as based on price alone is not sup-
ported by the specification, and otherwise, renders other
claims internally inconsistent. It also claims that “allo-
cating” and “matching” are not distinct processes, and
instead, that “allocating” is part of the “matching” proc-
ess.
    The plain language of the ’707 Patent shows that
“matching” cannot be based on price only. Claim 35
recites: “matching a remaining portion of the incoming
order or quotation . . . against professional orders and
quotations with larger size based on the allocating pa-
rameter.” ’707 Patent, col.35 ll.44-47. Claim 2 also pro-
vides that matching is based on a pro rata basis. Id. col.30
l.18. Additionally, claim 4 recites matching based on an
allocation formula. Id. col.30 l.55. Thus, the claim lan-
guage supports ISE’s argument that “matching” cannot be
based on price only.
    The specification offers further support for ISE’s con-
tention. It provides that “when all stored public customer
orders at the best price have been matched, then profes-
sional orders and quotations are matched on a pro rata
basis.” ’707 Patent, col.6 ll.1-3 (emphasis added). “Time
priority” is another basis on which “matching” can occur:
“In this case, [Professional] #1 and [Professional] #2 have
the same size, which is greater than [Professional] #3.
Because [Professional] #1 has time priority over [Profes-
CHICAGO BOARD   v. INTL SECURITIES                         16


sional] #2, [Professional] #1 gets matched first.” Id. col.18
ll.63-66 (emphases added). 4 Thus, while price is one basis
that may apply to all matches, it is not the only basis of
“matching.”
    The parties also dispute whether and to what extent
“matching” and “allocating” are distinct or of the same
process. While ISE appears to concede that “matching”
and “allocating” are different, it maintains that they are
part of a single process. 5 CBOE disagrees contending
that “allocating” is a process that is distinct from “match-
ing.” We conclude that “matching” and “allocating” are,
indeed, distinct processes.
    The claim language supports this distinction. Claim 1
recites, in relevant part, a processor means:
    for allocating portions of the incoming order or
    quotation . . . , wherein the allocating parameters
    include parameters for allocating a first portion of
    the incoming order or quotation . . . and allocating


    4   As discussed above in reference to claim 35, orders
and quotations may further be matched based on size:
“[Professional] #2 now has the largest size and 66% of the
size at the highest bid (20/30) and is matched for 14
contracts, leaving 7 contracts. [Professional] #3, the last
remaining professional, trades the balance of 7 contracts.”
’707 Patent, col.19 ll.1-4 (emphases added).
    5   CBOE contends that ISE is precluded from argu-
ing that “allocating” and “matching” are not different and
that matching is not based on price because it agreed
otherwise during the Markman hearing. A review of the
hearing transcripts does not support CBOE’s contention.
ISE did not represent that “allocating” and “matching”
were distinct. On the contrary, ISE expressly stated on
the record that the two terms were different yet part of
the same process. J.A. 9011-13.
17                         CHICAGO BOARD   v. INTL SECURITIES


     a remaining portion of the incoming order or quo-
     tation . . . .
’707 Patent, col.30 ll.5-13 (emphases added). Dependent
claim 2 provides a further limitation to claim 1: ”[t]he
exchange according to claim 1, wherein processor means
further comprises means for matching the remaining
portion . . . .” Id. col.30 ll.15-18 (emphasis added). These
claims indicate that “matching” and “allocating” are
distinct because “the presence of a dependent claim that
adds a particular limitation gives rise to a presumption
that the limitation in question is not present in the inde-
pendent claim.” 6 Phillips, 415 F.3d at 1315. This pre-
sumption is not rebutted by the specification.            In
describing the Trading Process, the specification provides:
     As a first example . . . [a]t step S170, the bid
     matching process determines that all 4 contracts
     in the incoming order have [to] be matched. The
     match between the incoming order and the cus-
     tomer order in the book memory 33 is sent to the
     execute trade process 27 in step S172.
     As a second example . . . . [a]s shown in FIG. 4(a),
     the bid matching process 34 completes step S168
     as above, matching 10 contracts of the incoming

     6   Other claims recite similar limitations that dis-
tinguish between “allocating” and “matching.” Specifi-
cally, claim 35 provides “second matching a remaining
portion of the incoming order or quotation preferentially
against professional orders and quotations with larger
size based on the allocating parameter.” ’707 Patent,
col.35 ll.44-47 (emphasis added). Depending on claim 35,
claim 36 recites: “The process according to claim 35,
wherein the step of second matching further comprises
allocating the remaining portion among the plurality of
professional orders and quotations on a pro rata basis.”
’707 Patent, col.35 ll.48-51 (emphasis added).
CHICAGO BOARD   v. INTL SECURITIES                        18


   order with the public customer order to sell 10
   contract[s] at 3 1/2. At step S170, however, the bid
   matching process 34 determines that there are
   still 20 contracts . . . . The bid matching process
   then applies the allocation algorithm as illus-
   trated in FIG. 4(b).
   FIG. 4(b) shows an allocation formula for match-
   ing incoming orders against quotations and pro-
   fessional orders at the best price . . . . [T]he
   balance of the incoming order of 20 contracts is al-
   located among [different Professionals] according
   to the following formula . . .
’707 Patent, col.16 ll.1-34 (emphases added). As the first
example indicates, all incoming orders initially are
“matched” to public customer orders, and where no incom-
ing orders remain to be filled, the order is executed. In
the second example, the incoming order is initially
“matched” to the available public customer orders. Where
there are remaining incoming orders, the balance of the
incoming order is then “allocated” among quotations and
professional orders. In addition, the ’707 Patent’s ab-
stract describes an “exchange [that] allocates the match-
ing of orders first to fill customer orders and then to fill
professional orders on a pro rata basis.” These examples
show that “matching” occurs at some point that is distinct
from “allocating.”
    Based on the claims and the specification, we conclude
that “allocating” and “matching” are distinct processes.
We often assume different terms convey different mean-
ings. SEB S.A. v. Montgomery Ward & Co., Inc., 594 F.3d
1360, 1369 (Fed. Cir. 2010) (citation omitted). The ’707
Patent does not teach otherwise in this instance. Accord-
ingly, we construe “matching” as “identifying a counter-
part order or quotation for an incoming order or
19                        CHICAGO BOARD   v. INTL SECURITIES


quotation.” We hold that “matching” is a process that is
distinct from “allocating.”
                            C.
     Although the district court did not err in holding that
the ’707 Patent disavowed all floor-based exchange sys-
tems, it did err in determining that “automated exchange”
describes a “method.” The district court construed “auto-
mated exchange” to mean “a method for executing trades
of financial instruments that is fully computerized, such
that it does not include matching or allocating through
use of open outcry.” J.A. 27. It also construed “exchange”
as “a method for executing trades of financial instru-
ments,” and construed “automated” to mean “fully com-
puterized, such that its protocol does not include
matching or allocating through use of open-outcry in order
to execute trades.” Id. The district court further ex-
plained that “a method that effects trades of financial
instruments by automatically matching and allocating
but also entails ‘oral communications between market
professionals at a central location in open view of other
market professionals’ is not fully computerized and there-
fore not ‘automated.’” Id. This construction was based
largely on the district court’s holding that the ’707 Patent
disavowed traditional floor-based trading. J.A. 7, 27.
     We have recognized that “[w]here the specification
makes clear that the invention does not include a particu-
lar feature, that feature is deemed to be outside the reach
of the claims of the patent, even though the language of
the claims, read without reference to the specification,
might be considered broad enough to encompass the
feature in question.” Honeywell Int’l, Inc. v. ITT Indus.,
Inc., 452 F.3d 1312, 1319 (Fed. Cir. 2006) (quoting SciMed
Life Sys. v. Advanced Cardiovascular Sys., 242 F.3d 1337,
1341 (Fed. Cir. 2001)). Here, we agree with the district
CHICAGO BOARD   v. INTL SECURITIES                      20


court and find that the ’707 Patent disavows traditional
floor-based trading.
     The Patent describes a system of trading options con-
tracts in these floor-based environments as an “open-
outcry” system because trading takes place through oral
communications between market professionals at a cen-
tral location in open view of other market professionals.
’707 Patent, col.1 ll.24-28. The Patent characterizes the
open-outcry system as “antiquated,” but it explains that
because of efforts to preserve the traditional system, the
transition to and use of computer-based technology on
options exchanges has been slow. Id. col.1 ll.34-37. While
floor-based exchanges employ some level of automation in
the execution and allocation of orders, the specification
recites that such exchanges have “inherent inadequacies”
and “deficiencies [that] make it difficult to assess market
depth and liquidity [which] ultimately impact the quality
of the prices customers receive for their order.” Id. col.2
ll.19-24, 59-67. The Patent further discloses that the
disjointed nature of the various manual, and occasionally
automated, systems used in floor-based exchanges culti-
vate these deficiencies, and again, make it difficult to
assess the true market depth and liquidity ultimately
impacting the quality of prices. Id. col.4 ll.47-51. The
Patent suggests that the increasing volume of trades in
options contracts, as well as the speed at which price
information of underlying stocks is transmitted to con-
sumers, have increased the demand for faster execution of
trades. Id. col.4 ll.34-37. The Patent proposes an auto-
mated exchange for the express purpose of remedying
these perceived deficiencies.
    The ’707 Patent thus disavows the traditional open-
outcry or floor-based trading systems. There is no other
way to interpret the listing in the specification of the
many reasons why manual and partially automated
21                        CHICAGO BOARD   v. INTL SECURITIES


exchanges cannot sustain the growing demands of the
market. Indeed, the specification goes well beyond ex-
pressing the patentee’s preference for a fully automated
exchange over a manual or a partially automated one, and
its repeated derogatory statements about the latter rea-
sonably may be viewed as a disavowal of that subject
matter from the scope of the Patent’s claims. Honeywell
Int’l, Inc., 452 F.3d at 1319.
    ISE nonetheless argues that the ’707 Patent does not
disavow all aspects of the traditional floor-based system
because it does not require a trading system to execute all
trades automatically. This argument misconstrues the
district court’s construction of “automated exchange.” The
district court’s construction requires that such an ex-
change be “fully computerized, such that it does not
include matching or allocating through use of open out-
cry.” J.A. 7.
    In addition, ISE contends that the district court erred
in construing “automated exchange” as a method rather
than a system for trading. CBOE argues that the district
court settled on the concept of a “method” in order to
differentiate the claims of the Patent from the way op-
tions contracts are traded in the traditional floor-based
environments. At least in this respect, ISE’s position has
merit.
     Once again, the claims are instructive. The ’707 Pat-
ent has seventeen independent claims. Eight of these are
system claims and nine are method claims. The system
claims are directed to “[a]n automated exchange for
trading a financial instrument,” e.g., ’707 Patent, col.29
ll.53-54, whereas the method claims recite “a process for
trading a financial instrument on an automated ex-
change,” e.g., id. col.35 l.23. Hence, “automated ex-
change” cannot be construed as a method when the
CHICAGO BOARD   v. INTL SECURITIES                            22


recited method or “process for trading a financial instru-
ment” is conducted on the “automated exchange.” The
specification also explains that: “[o]ver time, each of the
existing options exchanges has developed systems to track
the best quotation . . . ,” id. col.2 ll.2-3; that “[i]t is an
advantage of the invention to provide an automated
system for matching previously entered orders and quota-
tions . . . ,” id. col.4 ll.54-56; and that “[i]t is to be under-
stood that the exchange according to the invention
simultaneously provides a market for a series of options . .
. . The vast number of options that can be traded makes
the invention particularly advantageous over less auto-
mated systems . . . ,” id. col.6 ll.49-55 (emphases added).
     In this instance, proper claim construction may not
vary from the Patent’s own description of “automated
exchange” as being a system. Accordingly, while we
affirm the district court’s determination that the “auto-
mated exchange” disavowed the open-outcry system, we
cannot adopt the district court’s construction of “auto-
mated exchange” as a “method.” Instead, we construe
“automated exchange” to mean “a system for executing
trades of financial instruments that is fully computerized,
such that it does not include matching or allocating
through the use of open-outcry.”
                               II.
    The district court did not abuse its discretion in deny-
ing CBOE’s motions for leave to amend its Complaint. On
October 25, 2007, the district court entered a scheduling
order that required the parties to move to amend their
respective pleadings by January 11, 2008. J.A. 1772.
CBOE deposed pertinent witnesses on April 6, 2009, May
22, 2009, and June 22-23, 2009 at which time CBOE
alleges that it discovered new facts concerning its inequi-
table conduct defense. J.A. 21. On September 16, 2009,
23                        CHICAGO BOARD   v. INTL SECURITIES


CBOE moved for a prior and separate bench trial on the
inequitable conduct allegations which the district court
granted. J.A. 64, Dkt. Nos. 182, 204. On November 4,
2009, CBOE moved for leave to file an amended Com-
plaint (“proposed November Second Amended Com-
plaint”). J.A. 66, Dkt. No. 209. On November 18, 2009,
ISE moved for summary judgment on the proposed
amended allegations of inequitable conduct. J.A. 3029.
On December 22, 2009, the district court denied CBOE’s
motion for leave to file the proposed November Second
Amended Complaint (“December 22, 2009 Order”), finding
that CBOE had not demonstrated the requisite “good
cause” to amend after the deadline set in the scheduling
order. J.A. 20-22. The district court also concluded that
CBOE had not pled the inequitable conduct allegations
with particularity pursuant to Federal Rule of Civil
Procedure 9 (“Rule 9”). J.A. 23-26. Based on CBOE’s
failure to plead sufficiently, the district court determined
that ISE’s motion for summary judgment on CBOE’s
inequitable conduct defense was moot. J.A. 26.
    On December 31, 2009, CBOE again sought leave to
amend its Complaint (“proposed December Second
Amended Complaint”). J.A. 5099. While finding this
pleading satisfied Rule 9, the district court nevertheless
denied the motion holding that CBOE had failed to show
good cause for its delay in seeking leave to amend (“Janu-
ary 27, 2010 Order”). J.A. 5100. CBOE contends that the
district court abused its discretion.
    A decision to deny a motion for leave to amend a
pleading raises an issue not unique to patent law, and
thus, we apply the law of the regional circuit in which the
district court sits. Juicy Whip, Inc. v. Orange Bang, Inc.,
382 F.3d 1367, 1370 (Fed. Cir. 2004). Here, we apply the
law of the Seventh Circuit and review a district court’s
denial of leave to amend a complaint for abuse of discre-
CHICAGO BOARD   v. INTL SECURITIES                       24


tion and “reverse only if no reasonable person could agree
with that decision.” Carroll v. Stryker Corp., 658 F.3d 675,
684 (7th Cir. 2011) (citation omitted).
     Applying this standard, we find no error in the dis-
trict court’s rulings of December 22, 2009 and January 27,
2010. In the December 22, 2009 Order, the district court
found that CBOE failed to show good cause by “not
provid[ing] any explanation for why it waited until No-
vember 4, 2009 to seek leave to file an amended com-
plaint.” J.A. 21. The district court found fault in CBOE’s
delay in seeking leave “particularly since it announced its
theory in its detailed memorandum in support of its
motion for a prior and separate nonjury trial which in-
cluded the proposed allegations” on September 16, 2009.
Id. The district court also found that “CBOE cannot claim
to be surprised that it has to amend its complaint to
assert these new bases for inequitable conduct [because]
CBOE is a sophisticated litigant and was notified by ISE
as early as August 6, 2009 that ISE expected any new
allegations would have to be made part of CBOE’s com-
plaint before CBOE could proceed further on them.” Id.
Because “CBOE . . . waited until after fact discovery had
closed (on June 23, 2009), the Markman hearing took
place, expert reports were exchanged, and two weeks
before dispositive motions were due to move to amend[,]”
without any explanation, the district court held that
CBOE’s delay did not reflect diligence. J.A. 21-22.
    The district court repeated this reasoning in denying
CBOE’s subsequent attempt to amend its Complaint. J.A.
5100. In the January 27, 2010 Order, the district court
noted that ISE had objected to the timeliness of the
proposed new allegations in August 2009 and again at the
time the parties were scheduling their meet and confer
conference on October 14, 2009. Id. The district court also
rejected CBOE’s claim that, “between September 16 and
25                        CHICAGO BOARD   v. INTL SECURITIES


November 4, it was seeking ISE’s consent to the amend-
ment [to include the new allegations] and, once it became
clear ISE would not consent, filed its motion four business
days later” as a basis for diligence. Id. The district court
found that “CBOE’s focus on other aspects of the litigation
in September and October does not serve as good cause in
this case, as its decision to set aside its inequitable con-
duct claims was a tactical one.” Id. We cannot say that
these determinations, either individually or collectively,
amount to an abuse of discretion.
    CBOE also contends that the Complaint was con-
structively amended when ISE consented to prior and
separate trial on the allegations in the proposed Novem-
ber Second Amended Complaint. However, the district
court expressly rejected CBOE’s efforts to amend its
pleading to include the proposed allegations because it
found that the allegations of the proposed November
Second Amended Complaint did not comport with Rule 9.
J.A. 23. As a result, the district court never considered
the merits of ISE’s motion for summary judgment on the
proposed allegations that were the subject of the pur-
ported “constructive amendment.” See Walton v. Jennings
Cmty. Hosp., 875 F.2d 1317, 1320 (7th Cir. 1989) (finding
constructive amendment where plaintiff originally
pleaded contract-based theory but at briefing on summary
judgment both parties included a tort based theory to
which the court viewed as viable and to which the court
ruled on the merits). Finally, the district court found that
the “more particularized allegations in CBOE’s [proposed
December Second Amended Complaint, while sufficient,]
would require another round of summary judgment briefs,
which would prejudice ISE.” J.A. 5100. These determina-
tions are supported by the record and do not amount to an
abuse of discretion.
CHICAGO BOARD   v. INTL SECURITIES                     26


                        CONCLUSION
    We vacate the district court’s judgment of nonin-
fringement and remand for further proceedings based on
this court’s interpretation of the “system memory means,”
“matching,” and “automated exchange.” We also affirm
the district court’s denial of CBOE’s motions for leave to
amend the Complaint.
    AFFIRMED-IN-PART, REVERSED-IN-PART,
      VACATED-IN-PART, and REMANDED.
Each party shall bear its own costs.
