                 FOR PUBLICATION

 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT


GLENN TIBBLE; WILLIAM BAUER;              No. 10-56406
WILLIAM IZRAL; HENRY
RUNOWIECKI; FREDERICK                        D.C. No.
SUHADOLC; HUGH TINMAN, JR., as            2:07-cv-05359-
representatives of a class of               SVW-AGR
similarly situated persons, and on
behalf of the Plan,
                 Plaintiffs-Appellants,

                  v.

EDISON INTERNATIONAL; THE
EDISON INTERNATIONAL BENEFITS
COMMITTEE, FKA The Southern
California Edison Benefits
Committee; EDISON INTERNATIONAL
TRUST INVESTMENT COMMITTEE;
SECRETARY OF THE EDISON
INTERNATIONAL BENEFITS
COMMITTEE; SOUTHERN
CALIFORNIA EDISON’S VICE
PRESIDENT OF HUMAN RESOURCES;
MANAGER OF SOUTHERN
CALIFORNIA EDISON’S HR SERVICE
CENTER,
              Defendants-Appellees.
2              TIBBLE V. EDISON INTERNATIONAL


    GLENN TIBBLE; WILLIAM BAUER;             No. 10-56415
    WILLIAM IZRAL; HENRY
    RUNOWIECKI; FREDERICK                       D.C. No.
    SUHADOLC; HUGH TINMAN, JR., as           2:07-cv-05359-
    representatives of a class of              SVW-AGR
    similarly situated persons, and on
    behalf of the Plan,
                     Plaintiffs-Appellees,     OPINION

                      v.

    EDISON INTERNATIONAL; THE
    SOUTHERN CALIFORNIA EDISON
    BENEFITS COMMITTEE, incorrectly
    named The Edison International
    Benefits Committee; EDISON
    INTERNATIONAL TRUST INVESTMENT
    COMMITTEE; SECRETARY OF THE
    SOUTHERN CALIFORNIA EDISON
    COMPANY BENEFITS COMMITTEE,
    incorrectly named Secretary of the
    Edison International Benefits
    Committee; SOUTHERN CALIFORNIA
    EDISON’S VICE PRESIDENT OF
    HUMAN RESOURCES; MANAGER OF
    SOUTHERN CALIFORNIA EDISON’S
    HR SERVICE CENTER,
                  Defendants-Appellants.



          Appeal from the United States District Court
              for the Central District of California
          Stephen V. Wilson, District Judge, Presiding
              TIBBLE V. EDISON INTERNATIONAL                        3

     Argued and Submitted En Banc September 8, 2016
                San Francisco, California

                    Filed December 16, 2016

   Before: SIDNEY R. THOMAS, Chief Judge, and
STEPHEN REINHARDT, BARRY G. SILVERMAN, M.
   MARGARET MCKEOWN, RICHARD A. PAEZ,
RICHARD R. CLIFTON, CARLOS T. BEA, MILAN D.
  SMITH, JR., JACQUELINE H. NGUYEN, PAUL J.
 WATFORD and MICHELLE T. FRIEDLAND, Circuit
                     Judges.

             Opinion by Judge Milan D. Smith, Jr.


                          SUMMARY *


        Employee Retirement Income Security Act

    On remand from the Supreme Court, the en banc court
vacated the district court’s judgment in favor of an employer
and its benefits plan administrator on claims of breach of
fiduciary duty in the selection and retention of certain mutual
funds for a benefit plan governed by ERISA.

    The court of appeals had previously affirmed the district
court’s holding that the plan beneficiaries’ claims regarding
the selection of mutual funds in 1999 were time-barred under
the six-year limit of 29 U.S.C. § 1113(1). The Supreme


    *
      This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
4            TIBBLE V. EDISON INTERNATIONAL

Court vacated the court of appeals’ decision, observing that
federal law imposes on fiduciaries an ongoing duty to
monitor investments even absent a change in circumstances.

    Rejecting defendants’ contention that the beneficiaries
waived the ongoing-duty-to-monitor argument, the en banc
court held that the beneficiaries did not forfeit the argument
either in the district court or on appeal. Rather, defendants
themselves failed to raise the waiver argument in their initial
appeal, and thus forfeited this argument.

    The en banc court distinguished Phillips v. Alaska Hotel
& Rest. Emps. Pension Fund, 944 F.2d 509 (9th Cir. 1991),
which held that when a fiduciary violated a continuing duty
over time, the three-year limitations period set forth in 29
U.S.C. § 1113(2) began when the plaintiff had actual
knowledge of a breach in a series of discrete but related
breaches. The panel held that Phillips did not apply to the
continuing duty claims at issue under § 1113(1). Thus, only
a “breach or violation,” such as a fiduciary’s failure to
conduct its regular review of plan investments, need occur
within the six-year statutory period of § 1113(1); the initial
investment need not be made within the statutory period.

    Looking to the law of trusts to determine the scope of
defendants’ fiduciary duty to monitor investments, the en
banc court held that the duty of prudence required
defendants to reevaluate investments periodically and to take
into account their power to obtain favorable investment
products, particularly when those products were
substantially identical—other than their lower cost—to
products they had already selected.

   The en banc court vacated the district court’s decisions
concerning the funds added to the ERISA plan before 2001
and remanded on an open record for trial on the claim that,
             TIBBLE V. EDISON INTERNATIONAL                  5

regardless of whether there was a significant change in
circumstances, defendants should have switched from retail-
class fund shares to institutional-class fund shares to fulfill
their continuing duty to monitor the appropriateness of the
trust investments. The en banc court also directed the district
court to reevaluate its award of costs and attorneys’ fees in
light of the Supreme Court’s decision and the en banc court’s
decision.


                         COUNSEL

Michael A. Wolff (argued), Jason P. Kelly, Sean E. Soyars,
Nelson G. Wolff, and Jerome J. Schlichter, Schlichter
Bogard & Denton, Saint Louis, Missouri, for Plaintiffs-
Appellants/Cross-Appellees.

Jonathan D. Hacker (argued), Meaghan VerGow, Robert N.
Eccles, and Walter Dellinger, O’Melveny & Myers LLP,
Washington, D.C.; Gabriel Markoff and Ward A. Penfold,
O’Melveny & Myers LLP, San Francisco, California;
Sergey Trakhtenberg, Southern California Edison Company,
Rosemead, California; for Defendants-Appellees/Cross-
Appellants.

Jay E. Sushelsky, AARP Foundation Litigation, and Melvin
Radowitz, AARP, Washington, D.C., for Amicus Curiae
AARP.

Stacey E. Elias, Trial Attorney; Elizabeth Hopkins, Counsel
for Appellate and Special Litigation, Washington, D.C.;
Timothy D. Hauser, Associate Solicitor for Plan Benefits
Security Division, and M. Patricia Smith, Solicitor of Labor,
United States Department of Labor, Washington, D.C.; for
Amicus Curiae Secretary of Labor.
6            TIBBLE V. EDISON INTERNATIONAL


S. Michael Chittenden and Thomas L. Cubbage III,
Covington & Burling LLP, Washington, D.C., for Amicus
Curiae Investment Company Institute.

Abbey M. Glenn, Alison B. Willard, and Nicole A. Diller,
Morgan Lewis Bockius LLP, San Francisco, California; for
Amicus Curiae California Employment Law Council.


                         OPINION

M. SMITH, Circuit Judge:

         FACTS AND PRIOR PROCEEDINGS

    Edison sponsors a defined-contribution 401(k) Savings
Plan (Plan), wherein “participants’ retirement benefits are
limited to the value of their own individual investment
accounts, which is determined by the market performance of
employee and employer contributions, less expenses.”
Tibble v. Edison Int’l, 135 S. Ct. 1823, 1826 (2015) (Tibble
IV). “Expenses, such as management or administrative fees,
can sometimes significantly reduce the value of an account
in a defined-contribution plan.” Id.

    In 2007, plaintiffs-appellants (beneficiaries) brought this
action against Edison and the other defendants (collectively,
Edison). The district court denied the beneficiaries’ motion
for partial summary judgment, and partially granted
Edison’s summary judgment motion. Tibble v. Edison Int’l,
639 F. Supp. 2d 1074, 1080 (C.D. Cal. 2009) (Tibble I). This
appeal concerns a claim that survived summary judgment;
namely, that Edison breached its fiduciary duties by offering
“higher priced retail-class mutual funds as Plan investments
when materially identical lower priced institutional-class
             TIBBLE V. EDISON INTERNATIONAL                    7

mutual funds were available (the lower price reflects lower
administrative costs).” Tibble IV, 135 S. Ct. at 1826.

    The Plan is governed by the Employee Retirement
Income Security Act (ERISA), 29 U.S.C. §§ 1001–1461.
The relevant ERISA statute of limitations is six years,
29 U.S.C. § 1113(1), and at least three of the disputed funds
were added more than six years before the complaint was
filed. Tibble IV, 135 S. Ct. at 1826. The district court
allowed the beneficiaries to present evidence that their
claims concerning those funds were timely because Edison,
within the six-year limitations period, “fail[ed] to convert the
retail shares to institutional shares upon the occurrence of
certain ‘triggering events’” that should have prompted a full
due-diligence review. Tibble v. Edison Int’l, No. CV 07-
5359 SVW (AGRx), 2010 U.S. Dist. LEXIS 69119, at *99
(C.D. Cal. July 8, 2010) (Tibble II).

    After a bench trial, the district court ruled for the
beneficiaries on the retail-class funds selected within the six-
year period, because Edison did “not offer[] any credible
explanation for why the retail share classes were selected
instead of the institutional share classes,” and “a prudent
fiduciary acting in a like capacity would have invested in the
institutional share classes.” Id. at *98. Indeed, the court held
that there was “no evidence that [Edison] even considered or
evaluated the different share classes” when the funds were
added. Id. at *81 (emphasis in original).

    As to the funds initially selected before the statute of
limitations, the district court held that the “triggering events”
proffered by the beneficiaries for two of the funds—a name
change because of a partial change in ownership of a sub-
advisor, and a name change related to a years-old ownership
change—were insufficient to trigger a full diligence review,
and that a change in strategy in a third fund—from small-cap
8            TIBBLE V. EDISON INTERNATIONAL

to mid-cap—triggered a review to which Edison responded
adequately by adding another small-cap option. Id. at *102–
07.

    On appeal to our court, the beneficiaries argued that the
district court should have allowed them to prove their claims
concerning funds selected before the relevant six-year
period. Tibble v. Edison Int’l, 729 F.3d 1110, 1119 (9th Cir.
2013) (Tibble III), vacated, 135 S. Ct. 1823, 1829 (2015). In
response, Edison acknowledged that it had a duty to monitor
the funds for changed circumstances that would make the
investment no longer prudent, but argued that the
beneficiaries did not show sufficiently changed
circumstances. Our vacated decision accepted Edison’s
contention, and noted that “the district court was entirely
correct to have entertained” the possibility of changed
circumstances, and correct to have found the circumstances
insufficient to trigger a response by Edison. Id. at 1120. We
thus concluded that any theory of a duty absent changed
circumstances amounted to a continuing violation theory
that we declined to read into the ERISA statute of
limitations. Id. at 1119–20.

     Plaintiffs successfully petitioned for certiorari, and the
Supreme Court reversed our decision concerning the statute
of limitations, holding that regardless of when an investment
was initially selected, “a fiduciary’s allegedly imprudent
retention of an investment” is an event that triggers a new
statute of limitations period. Tibble IV, 135 S. Ct. at 1826,
1828–29. The Court specifically rejected “the conclusion
that only a significant change in circumstances could
engender a new breach of a fiduciary duty.” Id. at 1827. We
were cautioned against “applying a statutory bar to a claim
of a ‘breach or violation’ of a fiduciary duty without
considering the nature of the fiduciary duty,” and told to
             TIBBLE V. EDISON INTERNATIONAL                 9

“recognize that under trust law a fiduciary is required to
conduct a regular review of its investment with the nature
and timing of the review contingent on the circumstances.”
Id. at 1827–28. The Court instructed us to decide “the scope
of [Edison’s] fiduciary duty” to monitor investments. Id. at
1829.

    The Court also left to us on remand “any questions of
forfeiture,” acknowledging Edison’s contention that the
beneficiaries “did not raise the claim below that [Edison]
committed new breaches of the duty of prudence by failing
to monitor their investments and remove imprudent ones
absent a significant change in circumstances.” Id.

    A panel of our court in Tibble v. Edison International,
820 F.3d 1041, 1048 (9th Cir. 2016) (Tibble V), concluded
that the issue was forfeited. We then ordered that the case
be reheard en banc, so the panel’s decision in Tibble V is
vacated. Tibble v. Edison Int’l, 831 F.3d 1262 (9th Cir.
2016).

    For the reasons discussed below, we vacate the district
court’s decisions concerning the funds added to the Plan
before 2001, and remand for trial on an open record on the
claim that, regardless of whether there was a significant
change in circumstances, Edison should have switched from
retail-class fund shares to institutional-class fund shares to
fulfill its continuing duty to monitor the appropriateness of
the trust investments. We also encourage the district court
to reevaluate its fee determination in light of the Supreme
Court’s decision, and our decision en banc.
10           TIBBLE V. EDISON INTERNATIONAL

     JURISDICTION AND STANDARD OF REVIEW

    We have jurisdiction pursuant to 28 U.S.C. § 1291. We
review summary judgment determinations de novo. Szajer
v. City of Los Angeles, 632 F.3d 607, 610 (9th Cir. 2011).

                          ANALYSIS

I. Applicable Law

     The applicable statute of limitations in this case is the
six-year limit of 29 U.S.C. § 1113(1)(A), which states that
“[n]o action may be commenced . . . with respect to a
fiduciary’s breach of any responsibility, duty, or obligation
. . . six years after [] the date of the last action which
constituted a part of the breach or violation.” As the
Supreme Court noted in Tibble IV, under this statute only a
“breach or violation,” not an original investment decision,
need occur to start the six-year statutory period. 135 S. Ct.
at 1827.

    Generally, we do not “entertain[] arguments on appeal
that were not presented or developed before the district
court.” Visendi v. Bank of Am., N.A., 733 F.3d 863, 869 (9th
Cir. 2013). “Although no bright line rule exists to determine
whether a matter [h]as been properly raised below, an issue
will generally be deemed waived on appeal if the argument
was not raised sufficiently for the trial court to rule on it.” In
re Mercury Interactive Corp. Sec. Litig., 618 F.3d 988, 992
(9th Cir. 2010) (internal quotation marks omitted).

II. Forfeiture

    Before addressing the statute of limitations and ERISA-
trust law issues remanded to us by the Supreme Court, we
address Edison’s claims that the issues presently on appeal
                TIBBLE V. EDISON INTERNATIONAL                           11

have been forfeited by the beneficiaries. We conclude that
the beneficiaries did not forfeit their failure-to-monitor
argument in either the district court or on appeal. Instead,
we conclude that Edison itself forfeited the forfeiture
argument in its initial appeal.

    A. There Was No Forfeiture by the Beneficiaries on
       Appeal

    We begin with the appeal. The beneficiaries argued in
their opening brief that:

         Defendants had a continuing duty to ensure
         that each of the Plans’ investment options
         was and remained prudent and had
         reasonable expenses. Merely because they
         allowed an imprudent fund into the Plan at
         one point does not mean Defendants could
         just leave it in the Plan forever. Within six
         years prior to the commencement of this
         action, Defendants could have switched the
         Plan out of the retail shares and into the
         institutional shares of three excluded mutual
         funds and saved the Plan millions in
         unnecessary fees. 1


    1
       Edison attempts to obscure this clear statement with irrelevant
specificity, noting that “Plaintiffs’ appellate briefs also did not raise the
argument . . . that the district court’s summary judgment orders
improperly barred plaintiffs from challenging Edison’s monitoring of the
pre-2001 mutual funds during the repose period, unless plaintiffs
established that the funds underwent significant changes.” But, having
lost at trial on the merits of the “significant changes” issue, the
beneficiaries argued simply that the district court should have allowed a
claim that “‘the last action which constituted a part of the breach’—using
12             TIBBLE V. EDISON INTERNATIONAL

Similarly, the beneficiaries argued:

         At any time in that six-year period
         Defendants could have switched from retail
         to institutional class shares. Their failure to
         do so caused the Plan to pay unnecessary,
         retail fees in each of those six years.
         Therefore, the “last action which constituted
         a part of the breach”—using retail class
         shares—occurred within six years and the
         “latest date on which the fiduciary could have
         cured the breach”—replacing retail with
         institutional shares—also occurred within six
         years.

And, the beneficiaries argued that “[f]und fiduciaries . . .
were under a continuing obligation to advise the Fund to
divest itself of unlawful or imprudent investments.” (Citing
Buccino v. Cont’l Assurance Co., 578 F. Supp. 1518, 1521
(S.D.N.Y. 1983)).

    Thus, the beneficiaries argued on appeal for an ongoing
duty to monitor investments and to remove imprudent
investments—a duty that was not limited to “changed
circumstances.” The theory was simply that: “[i]n light of
the continuing duty of prudence imposed on plan fiduciaries
by ERISA, each failure to exercise prudence constitutes a
new breach of duty, that is to say, a new claim”—squarely
embracing the theory accepted by the Supreme Court. See

retail class shares—occurred within six years.” That the beneficiaries’
later phrasing articulated both what the district court allowed (a
significant changes theory) and what the district court rejected (a pure
continuing duty to prudently monitor) does not show forfeiture of the
latter argument. Indeed, it was specifically raised in the beneficiaries’
opening brief.
             TIBBLE V. EDISON INTERNATIONAL                  13

Tibble IV, 135 S. Ct. at 1829. In response, Edison argued for
a duty that was limited to changed circumstances: “Plan
fiduciaries do have a continuing duty under ERISA to
monitor investment options for changed circumstances
rendering a once-prudent investment now imprudent, but
plaintiffs here allege no changed circumstances.” The
Tibble III panel accepted Edison’s limiting theory, but the
Supreme Court rejected it. The claim was not forfeited on
appeal.

   B. There Was No Forfeiture by the Beneficiaries in
      the District Court

   Nor did the beneficiaries forfeit their claim in the district
court. Edison’s post-trial briefing stated:

       The Court expressly held in its first summary
       judgment ruling that plaintiffs could not
       revisit the prudence of selecting mutual funds
       that became part of the Plan’s investment
       lineup more than six years prior to the filing
       of the Complaint. By challenging the
       prudence of maintaining retail share classes
       of the three “name change” funds, plaintiffs
       have done what the Court has forbidden, by
       attempting to resurrect claims that were
       properly held barred by the six-year statute of
       limitations.

(Emphasis added and citation omitted).           Given this
contemporaneous statement that any claim challenging the
prudence of maintaining retail share classes first selected
before the limitations period had been rejected on summary
judgment, it is hard to see how Edison can now argue that
the beneficiaries forfeited the argument by not presenting
“any evidence establishing that a prudent fiduciary would
14           TIBBLE V. EDISON INTERNATIONAL

have identified the alleged share-class issue during regular,
periodic reviews.”

    Simply put, the district court held at summary judgment
that because “the initial decision to add retail mutual funds”
was made outside of the six-year limitations period, “the
prudence claims arising out of these decisions are barred by
the statute of limitations.” Tibble I, 639 F. Supp. 2d at 1120.
And, the district court stated in its trial decision: “three
funds were added to the Plan before the statute of limitations
period; thus, Plaintiffs challenged the failure to switch to an
institutional share class upon the occurrence of certain
significant events within the limitations period.” Tibble II,
2010 U.S. Dist. LEXIS 69119 at *7 (emphasis added). The
district court used the causal “thus” to describe why
Plaintiffs relied on a “significant changes theory”: because
prudence claims arising out of the initial selection were
outside the statute of limitations, and barred by the summary
judgment order (absent changed circumstances).

    Edison also pointed to the district court’s questioning of
the beneficiaries’ expert, Dr. Steven Pomerantz, who
attempted to identify changed circumstances that would
have triggered a duty to switch the share class, such that the
claim would not be barred by the district court’s statute of
limitations ruling. In conversation with Pomerantz, the
district court said that it did not understand the connection
between a name change of a fund and whether Edison should
have switched to institutional class shares, and asked
whether Edison should have removed the funds even without
a name change. The court asked: “[w]ould you contend . . .
that during the relevant time period due diligence would
have required the plan to nevertheless buy an institutional
share class, all things being equal, assuming the institutional
share class had a lower fee?” Pomerantz mostly stuck to his
             TIBBLE V. EDISON INTERNATIONAL                    15

significant changes theory in response. Edison argued that
this exchange showed that the district court did not forbid a
duty-to-monitor claim; indeed, according to Edison, the
district court “invited Pomerantz to make [a duty-to-monitor
claim] . . . , but he refused to agree,” sticking to the
significant changes theory.

    It is certainly possible that the district court had forgotten
a portion of its voluminous summary judgment ruling, and
was at that time open to a theory imposing a continuing duty
in the absence of “changed circumstances.” Or it could be,
as the beneficiaries suggest, that the district court was
checking to see whether the theory Pomerantz was
articulating was in substance the same as the theory the
district court had excluded. It does not matter which
interpretation is correct, because neither shows forfeiture.
Whatever the intent behind the district court’s hypothetical
questions to an expert, they did not constitute a change in its
earlier ruling sufficient to put the beneficiaries on notice that
they could then, contrary to the court’s earlier ruling, put on
evidence to prove their preferred continuing duty theory.

     Finally, Edison emphasizes that the district court
allowed the beneficiaries to put on a continuing duty case
concerning a different investment, the Money Market Fund.
See Tibble II, 2010 U.S. Dist. LEXIS 69119 at *108–21. It
is true that the claims have much in common, and it is not
clear why the district court provided a distinct treatment of
the Money Market Fund. Perhaps it was because Edison
continued to negotiate the rate for the fund throughout the
period at issue, while Edison employed a “set it and forget
it” approach with the mutual funds. Whatever the reason,
that the district court allowed a similar claim as to the Money
Market Fund simply does not show that, contrary to both
sides’ understanding, the beneficiaries were allowed to put
16           TIBBLE V. EDISON INTERNATIONAL

on a monitor-and-remove-absent-significant-changed-
circumstances theory concerning the mutual funds.

    Because the beneficiaries—and Edison—reasonably
believed that the district court’s summary judgment order
precluded the duty to monitor claim, and because the
beneficiaries preserved the claim on appeal, it has not been
forfeited.

     C. Edison’s Own Forfeiture

    The beneficiaries argue that Edison forfeited its
forfeiture argument by failing to raise it in the initial appeal.
Edison did not argue forfeiture in the initial appeal consistent
with its understanding, as expressed in its post-trial motion,
that the district court’s summary judgment ruling barred
claims relating to the funds first selected before 2001.

    Edison argues that it did not raise forfeiture because the
beneficiaries did not articulate their continuing duty theory
before they submitted their Supreme Court briefing.
However, as discussed above, the beneficiaries raised the
continuing duty argument in their opening brief on appeal.
Edison therefore forfeited any potential forfeiture response
to that argument. And, even at the Supreme Court, where
the beneficiaries clearly presented their continuing duty
argument in their petition for certiorari, Edison responded
not that the beneficiaries had forfeited that claim, but
instead, that a fiduciary only has a “duty to monitor for
material changes in circumstances.” (Emphasis omitted).

III. Phillips Does Not Bar the Beneficiaries’ Claim

    In Phillips v. Alaska Hotel and Restaurant Employees
Pension Fund, 944 F.2d 509, 520–21 (9th Cir. 1991), we
held that the limitations period under a different subsection
               TIBBLE V. EDISON INTERNATIONAL                         17

of the ERISA statute of limitations, 29 U.S.C. § 1113(2),
begins when a plaintiff has actual knowledge of a breach.
When there is “a series of discrete but related breaches”
because a fiduciary violated a continuing duty over time, the
§ 1113(2) limitations period does not begin anew with each
related breach. Id.

    Phillips followed the plain language of the statute:
§ 1113(2) provides that the plaintiff’s “actual knowledge of
the breach” is measured from “three years after the earliest
date” of such knowledge. “Once a plaintiff knew of one
breach, an awareness of later breaches [of the same
character] would impart nothing materially new,” and
applying a “continuing violation theory [would] essentially
read[] the ‘actual knowledge’ standard out of [§ 1113(2)].”
Phillips, 944 F.2d at 520. Thus, we held that “[t]he earliest
date on which a plaintiff became aware of any breach . . .
start[s] the limitation period of § 1113[](2) 2 running.” Id.

    The district court in Tibble I misunderstood Phillips to
stand for the broad proposition that “[t]here is no ‘continuing
violation’ theory to claims subject to ERISA’s statute of
limitations.” Tibble I, 639 F. Supp. 2d at 1086. However,
Phillips did not reject a continuing violation theory for the
ERISA statute of limitations generally; it merely held that,
for claims subject to § 1113(2), the earliest date of actual
knowledge of a breach begins the limitations period, even if
the breach continues. When a plaintiff has actual knowledge
of a breach, § 1113(2) operates to keep her from sitting on
her rights and allowing the series of related breaches to

    2
      Our opinion identified the statute as § 1113(a)(2), but quoted from
and discussed § 1113(2). Because there is no subsection (a)(2) in § 1113,
the reference appears to have been in error, and Phillips’ holding applies
to § 1113(2).
18             TIBBLE V. EDISON INTERNATIONAL

continue. However, when a plaintiff does not have actual
knowledge of a breach of a continuing duty and § 1113(1)
applies, the rationale for Phillips’ continuing duty limit on
§ 1113(2) is no longer relevant. Thus, we hold that Phillips
is inapplicable to the continuing duty claims at issue here,
namely to 29 U.S.C. § 1113(1). 3

     The Supreme Court held that the fiduciary duty
identified in this case is continuing in nature, and that each
new breach begins a six-year limitations period under
§ 1113(1).     The Court recognized the breach as “a
fiduciary’s allegedly imprudent retention of an investment”
which results in a series of related breaches as the investment
is retained over time. Tibble IV, 135 S. Ct. at 1826, 1828–
29 (emphasis added). As the Court made clear, only a
“breach or violation,” such as a fiduciary’s failure to conduct
its required regular review of Plan investments, need occur
within the six-year statutory period; the initial investment
need not be made within the statutory period. Id. at 1827–
28.

IV. ERISA and Analogous Trust Law

    The Supreme Court tasked us with resolving “the scope
of [Edison’s] fiduciary duty” to monitor investments, while

     3
       The district court held that the beneficiaries’ claims were governed
by § 1113(1) because Edison did not produce undisputed evidence of the
beneficiaries’ actual knowledge of the alleged breaches, making
§ 1113(2) inapplicable. Tibble I, 639 F. Supp. 2d at 1086. We affirmed,
holding that, “because the[] beneficiaries’ trial claims hinged on
infirmities in the selection process for investments,” Edison’s contention
that “mere notification that retail funds were in the Plan menu” was
insufficient to satisfy the “actual knowledge” standard. Tibble III,
729 F.3d at 1121. The Supreme Court also applied § 1113(1). Tibble
IV, 135 S. Ct. at 1827.
             TIBBLE V. EDISON INTERNATIONAL                  19

“recognizing the importance of analogous trust law.” Id. at
1829. Edison’s fiduciary duty arises from ERISA, “a
comprehensive statute designed to promote the interests of
employees and their beneficiaries in employee benefit
plans.” Shaw v. Delta Air Lines, Inc., 463 U.S. 85, 90
(1983).     “An ERISA fiduciary must discharge his
responsibility ‘with the care, skill, prudence, and diligence’
that a prudent person ‘acting in a like capacity and familiar
with such matters’ would use.” Tibble IV, 135 S. Ct. at 1828
(quoting 29 U.S.C. § 1104(a)(1)). “These duties are the
highest known to the law.” Howard v. Shay, 100 F.3d 1484,
1488 (9th Cir. 1996) (internal quotation marks omitted). “To
enforce them, the court focuses not only on the merits of the
transaction, but also on the thoroughness of the investigation
into the merits of the transaction.” Id.

     ERISA fiduciary duties are derived from the common
law of trusts, so “courts often must look to the law of trusts”
to “determin[e] the contours of an ERISA fiduciary’s duty.”
Tibble IV, 135 S. Ct. at 1828. “Under trust law, a trustee has
a continuing duty to monitor trust investments and remove
imprudent ones . . . separate and apart from the trustee’s duty
to exercise prudence in selecting investments at the outset.”
Id. “[A] trustee cannot assume that if investments are legal
and proper for retention at the beginning of the trust, or when
purchased, they will remain so indefinitely.” Id. (quoting A.
HESS, G. BOGERT & G. BOGERT, LAW OF TRUSTS AND
TRUSTEES § 684, 145–46 (3d ed. 2009) [hereinafter Bogert
3d]). “Rather, the trustee must ‘systematic[ally] conside[r]
all the investments of the trust at regular intervals’ to ensure
that they are appropriate.” Id. (quoting Bogert 3d § 684, at
147–48). In fulfilling his duties, a trustee is held to “the
prudent investor rule,” which requires that he “invest and
manage trust assets as a prudent investor would”; that is, by
“exercis[ing] reasonable care, skill, and caution,” and by
20            TIBBLE V. EDISON INTERNATIONAL

“reevaluat[ing] the trust’s investments periodically as
conditions change.” Bogert 3d § 684.

    Additionally, pursuant to the Restatement (Third) of
Trusts, a trustee is to “incur only costs that are reasonable in
amount and appropriate to the investment responsibilities of
the trusteeship.”       RESTATEMENT (THIRD) OF TRUSTS
§ 90(c)(3); see also id. § 88. The Restatement further
instructs that “cost-conscious management is fundamental to
prudence in the investment function,” and should be applied
“not only in making investments but also in monitoring and
reviewing investments.” Id. § 90, cmt. b; see also id. § 88,
cmt. a (“Implicit in a trustee’s fiduciary duties is a duty to be
cost-conscious.”); Donahue v. Donahue, 182 Cal. App. 4th
259, 273 (2010) (reversing and remanding an award for
attorneys’ fees incurred by a trustee because the trial court
did not consider whether the trustee fulfilled his duty to be
cost-conscious in incurring the fees). As the Uniform
Prudent Investor Act observes: “Wasting beneficiaries’
money is imprudent. In devising and implementing
strategies for the investment and management of trust assets,
trustees are obliged to minimize costs.” Unif. Prudent
Investor Act § 7.

    It is beyond dispute that the higher the fees charged to a
beneficiary, the more the beneficiary’s investment shrinks.
As a simple example, if a beneficiary invested $10,000, the
investment grew at a rate of 7% a year for 40 years, and the
fund charged 1% in fees each year, 4 at the end of the 40-year
period the beneficiary’s investment would be worth


     4
     The funds Edison offered beneficiaries had expense ratios ranging
from 0.03% to 2%. Tibble I, 639 F. Supp. 2d at 1117.
                TIBBLE V. EDISON INTERNATIONAL                           21

$100,175. If the fees were raised to 1.18%, or 1.4%, 5 the
value of the investment at the end of the 40-year period
would decrease to $93,142 and $85,198, respectively.
Beneficiaries subject to higher fees for materially identical
funds lose not only the money spent on higher fees, but also
“lost investment opportunity”; that is, the money that the
portion of their investment spent on unnecessary fees would
have earned over time. Tibble II, 2010 U.S. Dist. LEXIS
69119, at *124–25. Pursuant to the aforementioned trust law
principles, a trustee cannot ignore the power the trust wields
to obtain favorable investment products, particularly when
those products are substantially identical—other than their
lower cost—to products the trustee has already selected.

    The beneficiaries request “a new trial on the issue of
whether [Edison] breached [its] fiduciary duties by
providing as Plan investments during the limitations period
mutual funds in a share class that was more expensive than
other share classes that were available to the Plan.” (Citing
Lam v. Univ. Of Haw., 40 F.3d 1551, 1554–55, 1566–67 (9th
Cir. 1994) (remanding for trial after reversal of summary
judgment)). The beneficiaries wrote that “[b]ecause [they]
were precluded from presenting [the continuing-duty-
absent-changed-circumstances] claims by the district court’s
erroneous interpretation of the limitations statute, there is no
record on which the Court can resolve this claim on appeal.”
We agree that the record does not establish exactly what
would have resulted from the application of the correct legal
standard, and accordingly remand on an open record for the


    5
      The district court found that, for Edison’s six retail class funds that
had institutional class funds available, each retail fund’s fees were 0.18%
to 0.4% higher than the corresponding institutional funds’ fees over the
2001–2009 period. Tibble II, 2010 U.S. Dist. LEXIS 69119, at *26–41.
22           TIBBLE V. EDISON INTERNATIONAL

district court to consider these issues in light of the principles
explicated by the Supreme Court and this opinion.

V. Attorneys’ Fees and Costs

    The beneficiaries also requested that we direct the
district court “to reconsider an award of costs and attorney
fees in light of the results of the trial on remand.” The
beneficiaries had originally sought nearly $2.5 million in
attorneys’ fees and nontaxable costs, and in response to the
court’s order, sought a reduced amount of $407,277.30 in
fees and $3,731.92 in costs. The district court held that even
if the attorneys’ fees request was appropriate, it would be
offset by the costs due to Edison as the prevailing party on
the majority of claims originally filed.

    In determining that the beneficiaries’ original fee request
should be drastically reduced, the district court expressed its
skepticism concerning the importance of the beneficiaries’
partial victory. Considering the Supreme Court decision that
followed, and our en banc decision in this case, we believe
that this case has far greater importance than the district
court believed it did at the time of its earlier fee
determinations. Accordingly, we direct the district court to
reconsider the fee issue in light of the significant amount of
work that has been required to vindicate an important ERISA
principle in our court and the Supreme Court.

                       CONCLUSION

    We VACATE the district court’s decisions concerning
the funds added to the Plan before 2001, and REMAND on
an open record for trial on the claim that, regardless of
whether there was a significant change in circumstances,
Edison should have switched from retail-class fund shares to
institutional-class fund shares to fulfill its continuing duty to
            TIBBLE V. EDISON INTERNATIONAL             23

monitor the appropriateness of the trust investments. The
district court is also directed to reevaluate its fee
determination in light of the Supreme Court’s decision and
this court’s en banc decision.
