246 F.3d 377 (5th Cir. 2001)
TAITA CHEMICAL COMPANY, LTD., PLAINTIFF-COUNTER           DEFENDANT-APPELLANT-CROSS APPELLEE,v.WESTLAKE STYRENE CORPORATION, DEFENDANT-COUNTER           CLAIMANT-APPELLEE-CROSS APPELLANT.
No. 00-30020
UNITED STATES COURT OF APPEALS, FIFTH CIRCUIT
March 23, 2001

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[Copyrighted Material Omitted][Copyrighted Material Omitted]


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Appeal from the United States District Court for the Western District of Louisiana


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Before Higginbotham and DeMOSS, Circuit Judges, and KENT*, District Judge.

Samuel B. Kent, District Judge

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Plaintiff-Counter Defendant-Appellant-Cross Appellee, Taita Chemical Co., Ltd. ("Taita"), appeals the District           Court's grant of summary judgment in favor of Defendant-Counter Claimant-Appellee-Cross Appellant,           Westlake Styrene Corporation ("Westlake"). Westlake cross-appeals, protesting the District Court's grant of a           partial summary judgment in favor of Taita and the dismissal of its counterclaim. For the following reasons we           affirm in part and reverse in part.

FACTUAL AND PROCEDURAL BACKGROUND

5
In 1990, four companies, including Taita, entered into a joint venture to form Westlake. The joint venture           shareholders owned Westlake in the following percentages: (1) Taita--40%; (2) BTR Nylex, Ltd.           ("BTR")--20%; (3) the Chao Group--20%; and (4) the Sumitomo Corporation and Sumitomo Corporation of           America--20%.1 Westlake produces and sells styrene monomer.


6
On January 15, 1991, Taita and Westlake entered into a contract known as the "Off-Take Agreement." This           long-term agreement was a take-or-pay contract, under which Taita agreed to purchase 40% of Westlake's           styrene monomer production capacity each month for the duration of the contract. Price was to be determined           on a monthly basis in accordance with the contract's pricing clause. This clause provided that each month Taita           was to receive the lowest of three alternative prices:

4. Price

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The Contract Price per pound of Product delivered or ordered for delivery, including Deemed Delivery, during           each month shall be the U.S. Gulf Coast Styrene Monomer prices, net after all discounts, for contract           transactions as last published in each month by DeWitt & Company, Incorporated in its Benzene & Derivatives           Newsletter, or the price for such month charged by WSC [Westlake Styrene Corp.] to a consumer under a firm           multi-year contract or the posted contract market price for comparable volumes of Product, whichever is lower.           Should such publication cease to be published, Buyer and Seller shall mutually select other representative           publications.


8
The meaning of this pricing clause and the parties' conduct with respect to its terms lies at the center of this           dispute. In essence, Taita argues that Westlake overcharged it for styrene because Westlake did not extend Taita           a lower price provided by Westlake to another customer as required under Taita's interpretation of the second           pricing mechanism. This second provision states that Taita shall receive "the price for such month charged . . . to           a consumer under a firm multi-year contract." The parties have referred to this provision as the "most favored           nations" clause, for the obvious reason that it ensures that Taita, as Westlake's largest investor and principal           styrene purchaser, will receive the best available price. Westlake disputes Taita's interpretation of the pricing           clause, but urges that, in any event, the evidence demonstrates that Taita undeniably acquiesced in Westlake's           differing reading of the contract.


9
A rather substantial factual dissertation is needed in order to lay the groundwork for the Court's otherwise brief           discussion. Many of these facts are not overtly disputed. Other facts, however, as well as what inferences should           be drawn from the undisputed facts, remain in issue. As this case comes before us following a grant of           Westlake's motion for summary judgment, our presentation of the facts is thus intentionally colored, to a degree,           by our obligation to view the evidence in the light most favorable to Taita.


10
The harbinger of this dispute could be seen as early as June 1994. At that time Ken O'Neill ("O'Neill"), then           Westlake's president, queried Taita regarding whether Taita would permit Westlake to enter into a long-term           contract to sell styrene to another customer at a lower price without Taita asserting its "most favored nations"           rights. Taita president Graeme Bulmer ("Bulmer") responded that Taita would immediately demand the lower           price in accordance with the contract. Thus, later that year, when Westlake entered into a contract to sell styrene           production, the contract included a "meet or release" clause, which excused performance if market prices for           styrene fell below an agreed level. Taita and Westlake apparently agreed that such a clause prevented the           contract from becoming a "firm multi-year contract" as is required to trigger Taita's "most favored nations" rights.           Therefore, despite this foreshadowing, the pricing issue did not ripen until the end of 1994.


11
Then in December 1994, Westlake's outgoing president, O'Neill, recommended to the Westlake board that it           approve several multi-year contracts to sell styrene, including deals with Novacor Chemicals, Inc. ("Novacor")           and Cook Composites & Polymers Company ("Cook Composites").2 The Novacor agreement involved the           sale of roughly 25% of the monthly volume that Taita was required to purchase from Westlake, while the Cook           Composites arrangement was for less than 10% of Taita's purchase volume. Thus, although Novacor and Cook           Composites were both to be purchasing smaller volumes of styrene than was Taita, they nonetheless were to           receive lower prices than Taita was paying.


12
Soon thereafter, Taita, through O'Neill, now its new president, pointed to the Off-Take Agreement's "most           favored nations" clause and demanded that Westlake honor its right to receive the lower price provided to           Novacor.)3 Steve Bayless ("Bayless"), Westlake's new president, initially extended the Novacor discount to           Taita. On March 29, 1995, however, Bayless changed his stance, basing his reversal upon a legal opinion           regarding the meaning of the "most favored nations" clause. Westlake's attorney opined that Taita was entitled to           a discount for a "firm multi-year contract" only if the sale was for a quantity "comparable" to Taita's volume.           Because Novacor was only purchasing 25% of Taita's amount, Bayless informed Taita that the discount had           been granted in error. According to Westlake, it only granted Taita the Novacor price in the first place, because           outgoing Westlake president O'Neill informed Bayless that Taita was entitled to the lower price. After apprising           Taita of Westlake's self-perceived error, Bayless demanded that Taita remit the amounts it had underpaid for           styrene delivered in January and February. At first, Taita did not comply. Taita's internal correspondence           indicates that it was contemplating how to best advance its position with regard to the sought-after pricing.4


13
While Taita dithered and declined to show its hand, Bayless, on May 9, 1995, further corresponded with Taita,           arguing that Taita remained in breach of the Off-Take Agreement and, further, threatened to cut off Taita's           styrene supply if Taita did not remit the amounts past due. As of May 31, 1995, Taita had not yet paid           Westlake, despite indicating that it would do so, albeit under protest. This prompted another facsimile letter from           Bayless to Taita, and yet another on June 9, 1995, by which time Taita had fallen further behind on its payments.           At this juncture, Taita finally acceded to Bayless' request, becoming current and paying invoices in full as they           came due. Taita's payments did not, however, specifically indicate that they were being made "under protest."           Taita nevertheless contends that its compliance with Bayless' request, and its continued payment of invoices as           received, did not indicate any agreement on its part with the position urged by Westlake. Instead, Taita alleges           that it could not risk losing its source of styrene supply at that time, and, moreover, it felt that the pricing issue           might have been about to become moot, at least prospectively, in light of a contemplated arrangement between           the several Westlake stockholders.5


14
Purportedly, Taita had also chosen to bide its time on the pricing issue until a "firm multi-year contract" was           signed and executed, and Westlake in turn refused to supply Taita at the lower price. By September 1995, such           a situation had clearly presented itself. Westlake and Cook Composites had signed their contract (mentioned           above in the context of the December 1994 board meeting) and pricing was made retroactive to the first of the           year.6 Graeme Bulmer, now Taita's chairman, thus resurrected Taita's protest.


15
Bulmer wrote Westlake's Bayless to confirm Taita's understanding that the Cook Composites contract provided           a more favorable price than Taita was receiving. Bulmer's inquiry, in a September 18, 1995 letter regarding           Westlake's proposed 1996 budget, questioned whether Westlake's budget reflected Taita's right to receive the           lower price seen in the now finalized, and thus "firm," Cook Composites agreement. Bayless responded that the           Cook Composites price was not for a comparable volume, and that he believed that Taita's discount argument           had already been considered and rejected earlier in 1995. In this regard, Bayless pointed to Taita's alleged           acquiescence in Westlake's position with respect to the previously sought after Novacor contract-based           discount.


16
Several days later, on September 26, 1995, Bulmer responded to Bayless by contending that Taita had only paid           the disputed Novacor amounts because the Novacor contract was not "firm," as it had not been formally signed           and approved by the Westlake board. Bayless responded with surprise and reiterated Westlake's view that Taita           had waived its right to complain by paying the invoices following the parties' prior skirmish over Taita's claimed           Novacor-based "most favored nations" rights. On October 9, 1995, Bulmer sent a final letter to Bayless in which           he noted Taita's disagreement with Westlake's position and indicated that Taita would respond further under           separate cover. Bulmer had in fact drafted a harsh letter, on October 3, setting forth Taita's position of objection           in detail, but he never sent this letter per the instructions of BTR's managing director Phillip Aiken, who           apparently wished to deal with the dispute at an upcoming November 1995 Westlake board meeting. Neither           Taita nor BTR raised the pricing issue at this meeting, and Taita's and BTR's board members voted to approve           the proposed 1996 budget, which did not include discounts for Taita.7


17
This September and October 1995 round of correspondence was the last formal exchange between the parties           on this disputed pricing issue. They continued to negotiate, however, on efforts to terminate the Off-Take           Agreement, or for BTR and Taita to divest themselves of their Westlake holdings. Taita alleges that it did not           wish to actively press the "most favored nations" pricing issue in late 1995, via litigation or otherwise, because of           the sensitivity of these ongoing efforts. Taita does, however, point to evidence purportedly indicating that it had           not agreed to Westlake's interpretation of the pricing agreement, and that Westlake, in fact, knew Taita           continued to disagree. First, Allen Grassedonio ("Grassedonio"), a BTR employee who worked at Westlake,           had created a spreadsheet at the direction of Taita's president, O'Neill, that set forth Westlake's "Potential           Favored Nations Liability" to Taita. Grassedonio testified in his deposition that he placed copies of these           spreadsheets in the in-box of Westlake's president on at least two occasions during 1995 and 1996. Westlake's           two presidents during this time frame, Bayless and Dr. Ron Gilbert, deny receiving these reports. Grassedonio,           however, has testified that he confirmed by conversation, at least with Bayless, that this report was received.           Additionally, Grassedonio claims to have overheard Bayless having a conversation that he believed concerned           the spreadsheet's content with another Westlake executive. Taita also points to the March 1996 report of the           Westlake Evaluation Committee. This report sets forth valuation scenarios in contemplation of the Chao Group's           purchase of Taita's and BTR's shares in Westlake. Indisputably this report states that one valuation "assumes           [C]ook pricing for Taita."8 Finally, Taita notes the uncharacteristic lack of a release in the parties ultimate           agreement to part ways.


18
However, despite Taita's contention that it never agreed with Westlake's interpretation of the pricing clause, and           in stark juxtaposition with its cited evidence of non-acquiescence, Taita continued to pay Westlake's invoices as           they came due. It is thus undisputed that for the next fourteen months, from November 1995 - December 1996,           Taita paid each undiscounted invoice it received.


19
In December 1996, BTR finally sold its, and Taita's, combined 60% interest in Westlake to the Chao Group. As           a result of this sale, the Off-Take Agreement was effectively canceled, with BTR agreeing to continue purchasing           styrene from Westlake under a different pricing formula. As mentioned, the termination agreement did not include           any type of release of claims as between the parties.


20
Soon thereafter, BTR sold Taita, and in the summer of 1997, Taita's new shareholders became aware of the           potential claim that Taita had against Westlake for styrene overcharges. Taita then filed suit, on December 9,           1997, alleging $18 million dollars in damages. Taita advanced claims for: (1) breach of contract, premised on           Westlake's failure to extend Taita its "most favored nations" discount based upon the Cook Composites contract           and (2) payment of a thing not owed.9 In the District Court, below, Taita moved for partial summary           judgment regarding the meaning of the Off-Take Agreement's pricing clause. On this issue, the District Court           agreed with Taita and granted a partial summary judgment. Westlake cross-appeals this disposition. Taita's           victory, however, was merely pyrrhic, because the District Court held that Westlake had established several           affirmative defenses as a matter of law. Westlake successfully argued that Taita lost its right to benefit from the           "most favored nations" pricing clause through a modification, by waiver or by estoppel. Taita appeals the grant of           summary judgment on these affirmative defenses. Finally, Westlake had asserted a cross claim for breach of           fiduciary duty. The District Court dismissed this cross claim as mooted by the summary judgment. Westlake           cross-appeals this ruling.

DISCUSSION
I. Standard of Review

21
We review a district court's grant of summary judgment de novo. See Geoscan, Inc. of Texas v. Geotrace           Techs., Inc., 226 F.3d 387, 390 (5th Cir. 2000). Summary judgment is appropriate if no genuine issue of           material fact exists, and the moving party is entitled to judgment as a matter of law. See Fed. R. Civ. P. 56(c);           Celotex Corp. v. Catrett, 477 U.S. 317, 323, 106 S. Ct. 2548, 2552-53, 91 L. Ed. 2d 265 (1986). When a           motion for summary judgment is made, the nonmoving party must set forth specific facts showing that there is a           genuine issue for trial. See Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 250, 106 S. Ct. 2505, 2510, 91 L.           Ed. 2d 202 (1986). Issues of material fact are "genuine" only if they require resolution by a trier of fact. See id. at           248, 106 S. Ct. at 2510. The mere existence of some alleged factual dispute between the parties will not defeat           an otherwise properly supported motion for summary judgment. Only disputes over facts that might affect the           outcome of the lawsuit under governing law will preclude the entry of summary judgment. See id. at 247-48, 106           S. Ct. at 2510. If the evidence is such that a reasonable fact-finder could find in favor of the nonmoving party,           summary judgment should not be granted. See id.; see also Matsushita Elec. Indus. Co., Ltd. v. Zenith Radio           Corp., 475 U.S. 574, 587, 106 S. Ct. 1348, 1356, 89 L. Ed. 2d 538 (1986). Determining credibility, weighing           evidence, and drawing reasonable inferences are left to the trier of fact. See Anderson, 477 U.S. at 255, 106 S.           Ct. at 2513.


22
Procedurally, the party moving for summary judgment bears the initial burden of "informing the district court of           the basis for its motion, and identifying those portions of [the record] which it believes demonstrate the absence           of a genuine issue of material fact." Celotex Corp., 477 U.S. at 323, 106 S. Ct. at 2553; see also Fed. R. Civ.           P. 56(c). The burden then shifts to the nonmoving party to establish the existence of a genuine issue for trial. See           Matsushita, 475 U.S. at 585-87, 106 S. Ct. at 1355-56; Wise v. E.I. DuPont de Nemours & Co., 58 F.3d           193, 195 (5th Cir. 1995). The Court must accept the evidence of the nonmoving party and draw all justifiable           inferences in favor of that party. See Matsushita, 475 U.S. at 585-87, 106 S. Ct. at 1355-56. However, to meet           its burden, the non-movant "must do more than simply show that there is some metaphysical doubt as to the           material facts," but instead, must "come forward with 'specific facts showing that there is a genuine issue for trial.'"           Id. at 586-87, 106 S. Ct. at 1355-56 (quoting Fed. R. Civ. P. 56(e)).

II. The Pricing Clause

23
Westlake argues, by way of cross-appeal, that the District Court erred in determining that the pricing clause in           the Off-Take Agreement is unambiguous. The parties agree that the pricing formula clearly provides for three           distinct means of calculating the appropriate price per pound of styrene monomer. Moreover, the agreement also           indisputably sets forth that Taita was to pay only the lowest of these three plausible prices. What is at issue           between the parties is whether the phrase "for comparable volumes of product" was intended to modify each of           the three possible pricing mechanisms, or just the third means of price calculation. Westlake argues that the           "comparable volumes" language modifies not only the third pricing mechanism which it follows, but also the           second pricing calculation for "a firm multi-year contract." Taita argues that the District Court properly           determined that the language modifies only the third mechanism, which is not a basis for Taita's overcharge claim.


24
The parties agree that Louisiana law governs our analysis in this diversity of citizenship case. In Louisiana, the           interpretation of an unambiguous contract is an issue of law for the court. See Texas E. Transmission Corp. v.           Amerada Hess Corp., 145 F.3d 737, 741 (5th Cir. 1998). A court interpreting a contract shall determine the           "common intent" of the parties. La. Civ. Code Ann. art. 2045. However, "[w]hen the words of a contract are           clear and explicit and lead to no absurd consequences, no further interpretation may be made in search of the           parties' intent." Id. at art. 2046. Therefore, when the contract is not ambiguous, this Court lacks the authority to           look beyond the four corners of the document. See Texas E. Transmission Corp., 145 F.3d at 741. The District           Court found the language of the pricing clause "unequivocal." We agree. The "comparable volumes" language           clearly and unambiguously modifies only the third pricing mechanism, which is not relevant to the present           dispute.10 We therefore affirm the ruling of the District Court granting partial summary judgment regarding the           meaning of the pricing clause.

III. Westlake's Affirmative Defenses

25
After granting the partial summary judgment in Taita's favor regarding the meaning of the pricing clause, the           District Court turned to Westlake's various asserted affirmative defenses: modification, waiver and estoppel. The           District Court determined that Westlake had proven each of these three defenses as a matter of law, and thus           granted summary judgment.

A. Modification

26
The District Court held below, and Westlake now argues on appeal, that Taita's conduct served to modify the           Off-Take Agreement. The Louisiana Civil Code provides that a contract is an "agreement by two or more parties           whereby obligations are created, modified, or extinguished." La. Civ. Code Ann. art. 1906. In order for a           contract to be formed, both parties must consent. See id. at art. 1927. This consent may be manifested by a           writing, or be made orally, or by "action or inaction that under the circumstances is clearly indicative of consent."           Id. It follows that silence may also be a form of inaction indicating consent, provided that the silence "leads the           offeror to reasonably believe that a contract has been formed." Id. at art. 1942. Westlake, as the party asserting           modification, "must prove the facts or acts giving rise to the nullity, modification, or extinction." Id. at. art. 1831;           see also Allan v. Arnold, 673 F.2d 767, 669-70 (5th Cir. 1982); L & A Contracting Co., Inc. v. Ram Indus.           Coatings, Inc., 762 So. 2d 1223, 1232 (La. Ct. App. 2000); Big "D" Dirt Servs., Inc. v. Westwood, Inc., 653           So. 2d 604, 608 (La. Ct. App. 1995); Bank of Louisiana in New Orleans v. Campbell, 329 So. 2d 235, 237           (La. Ct. App. 1976). Moreover, it is well established that even if the written contract contains a provision           requiring that all modifications be in writing, as does the Off-Take Agreement, either oral agreement or conduct           can nonetheless prove modification. See Durham, Inc. v. Vanguard Bank & Trust Co., 858 F. Supp. 617, 621           (E.D. La. 1994); Wisinger v. Casten, 550 So. 2d 685, 687 (La. Ct. App. 1989); Campagna v. Smallwood, 428           So. 2d 1343, 1348 (La. Ct. App. 1983); Pelican Elec. Contractors v. Neumeyer, 419 So. 2d 1, 5 (La. Ct.           App. 1982); Pamper Corp. v. Town of Marksville, 208 So. 2d 715, 717 (La. Ct. App. 1968). In all instances,           however, the party urging modification must establish that parties mutually consented to the agreement as           modified. See La. Civ. Code Ann. art 1927; Society of the Roman Catholic Church of the Diocese of Lafayette,           Inc. v. Interstate Fire & Cas. Co., 126 F.3d 727, 737 (5th Cir. 1997); L & A Contracting, 762 So. 2d at 1232.


27
The issue therefore becomes whether Taita consented either expressly or impliedly to a modification of the           pricing clause, because modification requires a meeting of the minds. See La. Civ. Code Ann. art 1927;           Interstate Fire & Cas. Co., 126 F.3d at 737; L & A Contracting, 762 So. 2d at 1232. Obviously, the record           reflects a great amount of evidence favorable to Westlake in this regard. Taita paid some fourteen invoices after           making its last clear complaint regarding the styrene's price. Never, in submitting any of its payments for these           invoices, did Taita overtly and contemporaneously note that it was in any manner paying "under protest." Taita           and BTR, through their votes on the Westlake board, also voted to approve a budget that they knew did not           reflect providing Taita with a price discount. However, Taita does introduce evidence purporting to show that it           had not capitulated to Westlake's will on this issue, and that Westlake moreover knew it had not so agreed. In           this regard Taita points principally to: its prior protestations regarding the Novacor contract; its "last word" on the           issue, Bulmer's October 9, 1995 letter; the Grassedonio spreadsheet; and the Evaluation Committee's March           1996 pricing scenarios. This evidence, taken as a whole, creates a genuine issue of material fact as to whether           Taita agreed to modify the "most favored nations" pricing clause.11 See Illinois Cent. Gulf R.R. Co. v.           International Harvester Co., 368 So. 2d 1009, 1013 (La. 1979) (holding that in some instances the acceptance           of payments without protest for extended periods of time will not always constitute modification). Moreover, as           Taita contends, it seems that even if a modification occurred, Taita may nonetheless have been overcharged for           styrene up to the time of such modification. The District Court did not address this issue below, and we mention           it now only to stimulate further consideration of this issue on remand.

B. Waiver

28
Waiver is defined as the "intentional relinquishment of a known right, power, or privilege." Steptore v. Masco           Constr. Co., 643 So. 2d 1213, 1216 (La. 1994); see also Tate v. Charles Aguillard Ins. & Real Estate, Inc.,           508 So. 2d 1371, 1373 (La. 1987). In order for waiver to occur there must first be an existing right and           knowledge of that right's existence. See Steptore, 643 So. 2d at 1216. A party may then waive that right through           either: (1) "an actual intention to relinquish it," or (2) "conduct so inconsistent with the intent to enforce the right as           to induce a reasonable belief that it has been relinquished."12 Id. See also Gilbert v. B.D.O.W.S., Inc., 764           So. 2d 313, 320 (La. Ct. App. 2000). The party asserting waiver, here Westlake, must bear the burden of proof           on the issue. See F.D.I.C. v. Duffy, 47 F.3d 146, 150 (5th Cir. 1995); Tate, 508 So. 2d at 1375.


29
Westlake must therefore establish either that Taita: (1) intended to waive its rights under the contract or (2) acted           in a manner so inconsistent with this right as to induce a reasonable belief in Westlake that Taita did intend to           waive its right. Any effort by Westlake to establish that Taita intended to waive its "most favored nations" rights           fails at the summary judgment stage for the same reasons that Westlake's modification defense fails. Taita has           introduced enough evidence to create a fact issue on what it intended with respect to the pricing clause. The           second means of proving waiver, by conduct inducing a reasonable belief, likewise fails at the summary judgment           stage. This is so because Taita's objective evidence of its own intent is also probative of whether its conduct was           so inconsistent with its contractual rights as to induce a belief in Westlake of waiver; again creating a fact issue.           Moreover, Westlake fails to carry its summary judgment burden of demonstrating the reasonableness of its           beliefs. In this regard, we refer back to the untenable pricing clause interpretation advanced by Westlake, which           underlies this dispute. A reasonable juror could conclude that Westlake could not have reasonably believed that           Taita had waived it right to millions of dollars in overcharges based upon Westlake's audacious legal opinion. We           therefore reverse the District Court's waiver ruling.

C. Equitable Estoppel

30
The Louisiana Supreme Court has defined equitable estoppel as "'the effect of the voluntary conduct of a party           whereby he is precluded from asserting rights against another who has justifiably relied upon such conduct and           changed his position so that he will suffer injury if the former is allowed to repudiate the conduct.'" Morris v.           Friedman, 663 So. 2d 19, 25 (La. 1995) (quoting John Bailey Contractor v. State Dep't of Transp. & Dev., 439           So.2d 1055, 1059 (La. 1983)). The doctrine, in proper circumstances, will prevent a party "from taking a           position contrary to his prior acts, admissions, representations, or silence." John Bailey, 439 So. 2d at 1059-60;           accord Wilkinson v. Wilkinson, 323 So. 2d 120, 126 (La. 1975). Equitable estoppel thus has three elements:           "(1) A representation by conduct or work; (2) Justifiable reliance thereon; and (3) A change of position to one's           detriment because of the reliance." John Bailey, 439 So. 2d at 1059-60. However, equitable estoppel is           disfavored and should only be applied as needed to avoid injustice. See Morris, 663 So. 2d at 25-26; John           Bailey, 439 So. 2d at 1059. Accordingly, "a party having the means readily and conveniently available to           determine the true facts, but who fails to do so, cannot claim estoppel." John Bailey, 439 So. 2d at 1060.


31
Westlake's allegations in support of equitable estoppel are essentially as follows. Taita's conduct amounted to a           representation that it had no right to "most favored nations" pricing based upon the sale of a non-comparable           volume of styrene monomer. Westlake justifiably relied upon this representation to its detriment, in that it           permitted Taita and BTR to sell their interests in Westlake to the Chao Group. This sale terminated the Off-Take           Agreement, at a price that did not reflect a possible claim for overcharges by Taita. Thus, Westlake's present           shareholders were left with full liability for a claim for which Taita and BTR, as stockholders, would have born           60% of the financial burden.


32
Several items counsel against the District Court's decision to grant Westlake's Motion for Summary Judgment on           this issue. Taita has advanced evidence, as discussed above, that Westlake knew that it had not dropped the           overcharge issue. Additionally, under Louisiana law, Westlake cannot invoke equitable estoppel against Taita if           Westlake could have readily ascertained the true facts with respect to Taita's ongoing position regarding the           "most favored nations" clause. This duty to investigate is not a hollow pronouncement of horn-book law in           Louisiana. Rather, Louisiana courts regularly deny estoppel based, at least in part, on failures in this regard. See           Knippers v. Lambard, 620 So. 2d 1368, 1375 (La. Ct. App. 1993) (holding that plaintiff seeking estoppel had           failed to ensure that document had been received); Robbins Tire & Rubber Co., Inc. v. Winnfield Retread, Inc.,           577 So. 2d 1189, 1192 (La. Ct. App. 1991) (holding that a party seeking estoppel had an obligation to           determine the meaning of other party's silence); Duthu v. Allements' Roberson Mach. Works, 393 So. 2d 184,           186-87 (La. Ct. App. 1980) (noting that defendant's failure to reasonably question plaintiff's former husband or           to check public records, prevented estoppel based on plaintiff's payment of a judgment not owed); Twillie v.           H.B. Zachry Co., 380 So. 2d 747, 751 (La. Ct. App. 1980) (rejecting estoppel because plaintiff could have           sent a letter or made a phone call to determine a defendant's place of business). Thus, to the extent that Westlake           argues that Taita was impermissibly silent regarding the overcharges, one must also ask whether Westlake had a           culpable role in the misunderstanding. Giving proper deference to Taita on the inferences to be drawn from the           evidence produced, it strikes us that perhaps Westlake also was "laying behind the log." For instance, it seems           unusual that, in dissolving the Off-Take Agreement, Westlake did not obtain a release from Taita regarding           potential claims of whatever nature. Such releases are standard business practice even in situations where no           dispute was ever manifest. Moreover, Westlake's failure to ever so much as ask Taita if it had come to agree           with Westlake's view of the pricing clause further undermines the justifiableness required of Westlake's reliance.           In sum, Taita has introduced enough evidence, when viewed in a properly deferential manner, to create a material           issue of fact regarding equitable estoppel. Accordingly, we respectfully reverse the District Court's decision on           this issue.

IV. Payment of a Thing Not Owed

33
Taita also asserted a code-based cause of action for "payment of a thing not owed." See La. Civ. Code Ann. art.           2299. The District Court determined that Westlake's affirmative defenses barred this claim for the same reasons           that these defenses barred Taita's breach of contract claim. Because we reverse the District Court's summary           judgment based upon the affirmative defenses, we are compelled to reverse the dismissal of Taita's payment of a           thing not owed cause of action.13

CONCLUSION

34
The District Court properly granted partial summary judgment in favor Taita with respect to the proper reading of           the Off-Take Agreement's pricing clause. We therefore AFFIRM the District Court's decision in this regard.


35
With respect to the affirmative defenses advanced by Westlake, however, the District Court, despite a           protracted, meticulous and remarkably workmanlike effort, erred in granting summary judgment. We simply           cannot say with the requisite certitude that Westlake has carried its summary judgment burden of establishing any           one of its affirmative defenses as a matter of law. The imprimatur of a jury is important in a complex case such as           this, even if said jury ultimately reaches the same conclusion as that seen in the District Court's able analysis. We           therefore REVERSE the District Court's grant of summary judgment that was based upon Westlake's asserted           affirmative defenses. We likewise REVERSE the dismissal of Westlake's counterclaim, which is no longer moot           following our disposition. This matter is hereby REMANDED for proceedings consistent with this opinion.



*
 District Judge of the Southern District of Texas, sitting by designation.


1
 BTR held a 51% majority interest in Taita. Therefore, BTR and Taita collectively owned 60% of Westlake.


2
 Of some interest, at least with respect to Westlake's conspiratorial theory of this case, O'Neill left Westlake           to assume the presidency of Taita. At this December board meeting, O'Neill did not explain to the board that           these contracts could trigger Taita's right to a lower price. O'Neill has testified that he assumed each board           member was aware of such ramifications.


3
 The Novacor contract was allegedly closest to completion at this point and as such Taita's complaint in           early 1995 was based upon the Novacor contract, rather than the Cook Composites agreement that forms the           basis for Taita's lawsuit.


4
 It seems that Taita expressed uncertainty regarding whether the Novacor contract had been formally signed,           even though shipments to Novacor were ongoing. Taita allegedly did not want to press its pricing claim too           vigorously until it knew that the Novacor sale was a "firm multi-year contract" that would trigger the "most           favored nations" clause. In this regard it is helpful to note, as set forth above, that prior agreements by Westlake           to sell styrene at lower prices had included a "meet or release" clause, which excused performance if market           prices for styrene fell too low. Rightly or wrongly, the parties apparently had not viewed such arrangements as           "firm multi-year contracts." Thus, Taita believed that only particular types of styrene sales would trigger its "most           favored nations" rights.


5
 The Westlake stockholders were considering whether to take all styrene produced by Westlake under a           new proportionate off-take agreement, with each paying the same price. Although this course of action was           never ultimately taken, the stockholders allegedly continued to discuss the possibility from April to September           1995, during which time Taita did not wish to rock the boat. In September, however, the bottom fell out of the           styrene monomer market, which made it uneconomical for Westlake, and correspondingly its other investors, to           pursue this option.


6
 The Westlake board approved this contract at its July 21, 1995 meeting, at which time the Taita and BTR           board members made no mention of any intention to claim a discount. Westlake now counsels that this silence           was momentous, because the lost profit required to give Taita the later demanded discount would have exceeded           the total revenue from the Cook Composites deal, an arrangement that would of course accrue to the benefit of           only Taita and BTR, and not the other Westlake shareholders.


7
 Again Westlake cries foul, but Taita contends that approving a budget without reference to Taita's potential           claim was acceptable accounting and thus not inconsistent with its protest.


8
 The parties sharply disagree about the meaning of this report. The District Court adopted Westlake's view           that this report actually contemplated a scenario in which Taita would purchase the Chao Groups' interest and           then restructure the Off-Take Agreement in a manner similar to the Cook Composites deal. Hence the "Cook"           reference. This is certainly plausible, but so too is Taita's position which we are bound to give credence to at the           summary judgment stage.


9
 Taita's amended complaint also set forth claims of bad faith, duress, fraud, unjust enrichment, and an           alternative breach of contract claim based upon the "DeWitt" pricing mechanism. Taita's opening brief does not           address error with respect to these causes of action. Accordingly, we find that Taita has waived these claims.           See Carmon v. Lubrizol Corp., 17 F.3d 791, 794 (5th Cir. 1994) ("We liberally construe briefs in determining           issues presented for review; however, issues not raised at all are waived."). Taita's efforts by way or its reply           brief to preserve error on these claims is unavailing. See Cavallini v. State Farm Mut. Auto Ins. Co., 44 F.3d           256, 260 n.9 (5th Cir. 1995) ("[W]e do not consider issues raised for the first time in a reply brief.")


10
 Moreover, the DeWitt Newsletter price, which is the first pricing mechanism, apparently did not publish           volume information. The "comparable volumes" language, therefore, could not have been applicable to all three           mechanisms. Accordingly, it is apparent that reading the clause in the manner urged by Westlake would be           inconsistent with not only English grammar, but reality. In a tortured recognition of the inherent rhetorical flaws in           its argument, Westlake now argues that the "comparable volumes" language modifies only the second and third           pricing mechanisms. We reject this argument.


11
 Westlake makes much of two Louisiana cases in which the repeated paying of increased invoiced amounts           was held to indicate a modification of the parties' pricing agreement. See Ceco Corp. v. Mid-Gulf Constr., Inc.,           396 So. 2d 474, 476-78 (La. Ct. App. 1981); Stupp v. Con-Plex, Div. of U.S. Indus., 344 So. 2d 394, 396           (La. Ct. App. 1977). These cases, however, are distinguishable. In both of these cases, the buyer paid invoices           without any protest until after all needed goods had been delivered. Taita, by contrast, has set forth some           evidence of timely protest, from which a jury could conclude there had not been a modification. See Illinois Cent.           Gulf, 368 So. 2d at 1012-13 (noting that the question of modification is "essentially factual" and affirming a trial           court's determination that a lease had not been modified by accepting sixteen payments without complaint).


12
 Taita contends that Steptore and Tate have eased the traditional burden of proving waiver, by providing           that waiver may be established by the inducement of a reasonable belief even absent actual intent to waive.           According to Taita, these cases must be considered in the context of insurance coverage law, a situation in which           the parties have inherently unequal bargaining power that the Louisiana Supreme Court obviously sought to           ameliorate. We disagree. It may be true that the court expanded its definition of waiver to alleviate inequities in           the insurance context, but it nonetheless set forth a general concept that this Court has previously found broadly           applicable. See Specialty Healthcare Mgmt., Inc. v. St. Mary Parish Hosp., 220 F.3d 650, 656, 658 (5th Cir.           2000). Moreover, the most recent waiver pronouncement by a Louisiana appellate court undermines Taita's           argument. See Rogers v. Horseshoe Entm't, 766 So. 2d 595, 601 (La. Ct. App. 2000) (applying Steptore to the           terms of an option contract). We see no reason to depart from the Louisiana Supreme Court's pronouncement of           law that has been followed outside of the insurance law context. Moreover, we are bound by the earlier panel           decision of this Court. See F.D.I.C. v. Abraham, 137 F.3d 264, 267-69 (5th Cir. 1998) (discussing the           generally binding effect of Erie "predictions" by an earlier panel).


13
 The District Court ruling also discussed a difficult issue regarding a January 1, 1996 revision to the           Louisiana Civil Code. See La. Civ. Code. Ann. arts. 2298-2305. Westlake argues that prior to this revision, a           party could only recover payments that were not knowingly made in error. By contrast, post-revision, the code           establishes that unknown error is not a prerequisite to recovery. See id. We decline to reach the propriety of the           District Court's discussion of this issue. It seems to us that in a case involving an express contract such as this, the           viability of the code-based claim is congruent with the primary claim for breach of contract. Thus, there seems to           be no reason to make an unneeded prediction of Louisiana law when Taita's recovery under Article 2299 cannot           possibly exceed the amount it might recover on its breach of contract claim. We note, however, that the District           Court's discussion ignores a critical accrual issue: Taita made payments both before and after the code change.           Thus, to the extent that Taita's Article 2299 claim has some importance that we have overlooked, the accrual           issue would need to be addressed on remand.


