Opinion for the Court filed by Circuit Judge HARRY T. EDWARDS.
This appeal raises the issue whether, under the law of the District of Columbia, there can be an implied contractual duty arising under a 1974 construction contract obligating the Washington Metropolitan Area Transit Authority (“WMATA”) to avoid unreasonable delays in processing “equitable adjustment” claims, the breach of which would entitle an aggrieved contractor to an award of prejudgment inter
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est. Because this issue raises an unresolved question of local law, and because “[a] federal court ... should normally decline to speculate on such a question of local doctrine,”
Delahanty v. Hinckley,
I. BACKGROUND
In accordance with the certification procedures of the District of Columbia, we will set forth the facts relevant to the questions certified and the nature of the controversy in which the questions arose. See D.C. Code Ann. § ll-723(c) (1981). We recognize that this Background section is somewhat unusual in its length; this is because the antecedent case law, from the District of Columbia and from this court, is both extensive and confused. In the end, however, the certified questions are straightforward.
A. The Nature of the Controversy
WMATA, the appellant in this case, challenges an award of prejudgment interest to the appellee, Nello L. Teer Company (“Teer”), a construction contractor formerly doing business with WMATA; Teer cross-appeals the amount of that award. This action stems from a 1974 contract between WMATA and Teer for construction of the Clarendon Metrorail Station in Arlington, Virginia. The contract contains a standard “Changes” (“equitable adjustment”) clause, which provides in part:
If any [contract] change ... [attributable to WMATA] causes an increase or decrease in the Contractor’s cost of, or the time required for, the performance of any part of the work under this contract, whether or not changed by any order, an equitable adjustment shall be made and the contract modified in writing accordingly....
On December 1, 1976, Teer submitted a claim for an “equitable adjustment,” contending that WMATA’s delay in obtaining easements necessary for Teer to perform some of its work had caused Teer to incur more than $8 million in additional costs. On November 16, 1979, WMATA unilaterally adjusted the contract price by $592,814 to compensate Teer for those costs that it found properly attributable to WMATA’s delay, but determined that any other additional costs Teer may have incurred were due to its own “inefficient operation” rather than to WMATA’s actions. On December 4, 1979, Teer appealed this decision to the Board of Contract Appeals of the Army Corps of Engineers (“Board”). 1
Nearly seven years later, the Board issued its advisory opinion.
See Nello L. Teer Co.,
86-
On July 20, 1987, the General Manager of WMATA issued a final decision on *302 Teer’s claim, accepting the Board’s proposed increment for Teer’s increased costs, but, rejecting the recommendation of prejudgment interest on that amount. In reaching this decision, the General Manager stated that, as an interstate agency, WMATA was immune from an award of prejudgment interest “unless such interest is specifically provided for by statute or by contract.” Finding neither a statutory nor a contractual provision that specifically authorized an award of prejudgment interest in this case, the General Manager rejected the Board’s proposal as ill-founded as a matter of law.
Teer sought judicial review of the General Manager’s decision in the District Court of the District of Columbia, challenging both the adequacy of the equitable adjustment award and the General Manager’s refusal to pay prejudgment interest on the Board’s increase to the award. The District Court upheld the adequacy of the award as a whole, a ruling which Teer does not challenge. However, the trial court initially deferred judgment as to whether an equitable adjustment provision in a construction contract is sufficient to waive WMATA’s sovereign immunity from an award of prejudgment interest, pending this court’s resolution of that issue in
General Ry. Signal Co. v. WMATA,
B. The Antecedent Case Law on Prejudgment Interest
On May 12, 1989, a panel of this court issued its decision in
GRS II.
The court found that an equitable adjustment clause “imports into the contract a doctrine mandating a make-whole remedy that will restore a contractor to the contractor’s pre-change circumstances,” and declared that an award of prejudgment interest on sums expended by a contractor because of WMA-TA’s changes to a contract was necessary to restore the contractor to its
status quo ante.
Only five days later, however, the. District of Columbia Court of Appeals held that, as a matter of District contract law, an equitable adjustment clause in a 1968 construction contract did not authorize an award of prejudgment interest against the District. District of Columbia v. C.J. Langenfelder & Son, Inc., 558 A.2d 1155 (D.C.1989). The Court of Appeals emphasized the “fundamental principle” that contract provisions be construed so as to honor the parties’ reasonable expectations at the time they executed the contract. Id. at 1159. The court then reviewed pre-1968 case law and Contract Appeals Board decisions interpreting equitable adjustment terms in Government contracts, since contracting parties are presumed to be aware of the customary and common usage of their contract terms. Id. The court concluded that Langenfelder and the District had “executed their contract against a background of judicial and administrative interpretations which held that a contractor could not recover interest for delays in the resolution of contract disputes with the government.” Id. 3 The court in Langen- *303 /elder therefore found that the parties did not intend their 1968 contract to provide for prejudgment interest as part of a contractor’s equitable adjustment. Id.
The Langenfelder court expressly rejected this court’s analysis in GRS II. Id. at 1163. The Court of Appeals suggested that the GRS II court, in awarding a contractor prejudgment interest based on 1989 notions of equitable adjustments, had improperly reformed a contract negotiated by the parties years earlier against an entirely different legal background. See id. Lan-genfelder thus left no doubt that GRS II, as a matter of District law, incorrectly construed the scope of equitable adjustment terms in Government contracts executed in the early 1970s.
Teer claims that GRS II is still controlling precedent in this case—notwithstanding the, D.C. Court of Appeals decision in Langenfelder—because the WMA-TA/Teer contract was executed in .1974, rather than in 1971, when the contract at issue in GRS II was signed. Teer argues that Langenfelder's, rejection of GRS II merely indicated the D.C. Court of Appeals’ disapproval of this court’s interpretation of “equitable adjustment” clauses in 1971 contracts. Between 1971 and 1974, Teer maintains, the meaning of the term “equitable adjustment” had evolved to encompass prejudgment interest. We find this argument unpersuasive.
The rule that prejudgment interest on capital was not available to a Government contractor was apparently alive and well when WMATA and Teer entered into their contract. As the D.C. Court of Appeals observed in Langenfelder:
The [no-interest] rule was so engrained in the law of this jurisdiction that the D.C. Circuit noted that as ofl97Jp, “not a single court or board of contract appeals had allowed recovery of interest foregone on equity capital as a ‘cost of performance.’ ”
Unfortunately, our recognition of the limited force of GRS II does not resolve this case. In its post-GRS II opinion, the District Court noted an “apparent conflict” between GRS II and Langenfelder. However, while recognizing that Langenfelder had rejected GRS II, the District Court nonetheless held that prejudgment interest may be awarded under an equitable adjustment provision of a Government contract where, as here, the governmental agency has subjected a contractor to “unreasonable delay” in processing its claim. The District Court based this holding on an implied condition in the WMATA/Teer contract; it thus avoided the direct limits of Langenfelder.
In reaching this holding, the District Court relied primarily on this court’s summary affirmance pf an award of prejudgment interest in
General Ry. Signal Co. v. WMATA,
664 E.2d 296 (D.C.Cir.1980) (per
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curiam)
(“GRS F’), cert. denied,
WMATA contends that GRS I, like GRS II, is inconsistent with the District of Columbia Court of Appeals' decision in Lan-genfelder, and thus should not be followed. WMATA points out that Langenfelder itself involved a 20-year delay in settling the plaintiff’s equitable adjustment claim. Had the Court of Appeals intended to permit an exception to its rule against prejudgment interest for “unreasonable delay,” WMATA argues, it would assuredly have applied that exception in Langenfelder itself.
While we agree with WMATA that the
Langenfelder
decision places our
GRS I
holding in question, we do not believe that
Langenfelder,
of its own force, is sufficient authority for us to abandon
GRS I.
First the great majority of the time expended in settling the claim in
Langenfelder
was consumed by court delays, rather than delays at the administrative level which are more properly deemed, the responsibility of the Government agency..
See
Second, there is nothing in the Langen-felder opinion to indicate whether the plaintiff argued for prejudgment interest based on an unreasonable delay theory. Since the D.C. Court of Appeals apparently was never afforded the opportunity to consider this argument in Langenfelder, we can only speculate as to how that court will respond when faced with the issue. There is no need for us to set sail on such uncertain waters, however, when the safe harbor of the District’s certification procedure is so easily within our reach. We therefore ask the Court of Appeals to decide whether, under the law of the District of Columbia, there can be an implied contractual duty arising under a 1974 construction contract obligating WMATA to avoid unreasonable delays in processing equitable adjustment claims, the breach of which would justify a court’s award of prejudgment interest to the contractor.
C. Section 15-109 of the D.C.Code
Teer also has suggested that the prejudgment interest award in this case can be independently justified on the basis of section 15-109 of the D.C.Code, which permits trial courts to award prejudgment interest in breach of contract cases when necessary fully to compensate the plaintiff. In
Lan-genfelder,
however, the court expressly
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stated that an equitable adjustment claim “arises under the contract and is not in the nature of breach of contract.”
D. The Time Period for Calculating Prejudgment Interest
Should the D.C. Court of Appeals determine that an award of prejudgment interest could properly be made either on the basis of an implied condition that WMATA avoid unreasonable delay in processing Teer’s claim or on the basis of section 15-109 of the D.C.Code, we ask the court to answer a final question concerning the appropriate time period for calculating such an award. The District Court below affirmed the Board’s finding that interest should be calculated from December 4, 1979, when Teer’s administrative appeal was filed, rather than from the date when Teer completed the work, as Teer had suggested. Teer challenges this ruling as contrary to our decision in
Granite-Groves v. WMATA,
As we have noted above, the continued vitality of these authorities with regard to equitable adjustment claims has been placed in doubt by the
Langenfelder
decision. Moreover, the holding in
Granite-Groves
was undermined when
GRS II,
on which the District Court relied in making its interest calculation below, subsequently upheld an award of prejudgment interest limited to a period of unreasonable delay.
GRS II,
Rather than choose between the respective treatments of this issue in GRS II and Granite-Groves, we certify a third question to the D.C. Court of Appeals. Should the court find a local law basis for an award of prejudgment interest in this case, we ask it to determine whether such an award should be calculated: (1) from the time the equitable adjustment claim is first submitted; (2) solely for the period constituting the unreasonable delay; or (3) for either period, depending upon the facts and circumstances of the particular case, according to the discretion of the trial court.
II. The Certified Questions
In the absence of controlling precedent in the decisions of the D.C. Court of Appeals, and in light of the foregoing statement of facts relevant to the questions certified and the nature of the controversy in which the questions arose, we hereby certify to the D.C. Court of Appeals the following questions of law:
(1) Under the law of the District of Columbia, can there be an implied contractual duty arising under a 1974 construction contract obligating WMATA to avoid unreasonable delays in processing equitable adjustment claims, the breach of which would entitle the *306 contractor to an award of prejudgment interest?
(2) If a delay in processing an equitable adjustment claim does not justify an award of prejudgment interest under question (1), can section 15-109 of the D.C. Code furnish an independent basis for such an award?
(3) If prejudgment interest may be awarded pursuant to (1) or (2) above, does the trial court have discretion in limiting an interest award, or must the court as a matter of law either (i) award interest from the time that the claim is first submitted to WMATA or (ii) award interest only for the period of the unreasonable delay?
III. Conclusion
We hereby certify the foregoing questions of law to the District of Columbia Court of Appeals. The mandate shall issue forthwith and shall serve as the “certification order” from this court. See D.C.Code Ann. § ll-723(d). The Clerk of the Court shall forward copies of all or such portion of the record in this case as may be requested by the District of Columbia Court of Appeals. See id.
So ordered.
Notes
. The "Disputes" clause in the WMATA/Teer agreement provides that contract disputes be heard initially by the Board, which then issues an advisory opinion to the General Manager of WMATA. After reviewing the Board's opinion, the General Manager renders a final decision which is subject to judicial review in the United States district courts and the courts of Maryland and Virginia. See D.C.Code Ann. § 1-2439 (1981) and Section 81 of the Washington Metropolitan Area Transit Authority Compact, D.C. Code Ann § 1-2431 (1981).
. Actions based upon WMATA’s contracts are governed by "the law of the applicable signatory” to the WMATA Compact. Section 80, Washington Metropolitan Area Transit Authority Compact, D.C.Com: Ann. § 1-2431 (1981). Maryland, Virginia and the District of Columbia are the three signatories to the Compact. Although the issue was not raised below, the District Court relied on District of Columbia statutory and case law, as well as cases from this court applying District contract law, apparently on the assumption that the District was the “applicable signatory” in this case. Since neither party has objected to this choice of law, and we find no error in the choice made, we apply the contract law of the District as well.
See Lee v. Flintkote Co.,
. This finding related only to prejudgment interest
on equity capital
expended by a contractor as a result of the Government’s changes to a contract. As the Court of Appeals acknowledged,
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an exception to the "no-interest” rule was recognized where a contractor could demonstrate that it had paid interest
on borrowings
necessitated by contract changes.
Langenfelder,
. The District Court also cited three other cases in support of its holding. However, these cases (all decided before
Langenfelder)
do not stand for the proposition that a Government agency's unreasonable delay justifies an award of prejudgment interest to a Government contractor. Although prejudgment interest was awarded in both
District of Columbia v. Pierce Assoc., Inc.,
