(concurring in part and dissenting in part).
I agree with this opinion in all respects except one. I would reverse the trial court on its denial of prejudgment interest because these damages were certain, or capable of being made certain by calculation by reference to prevailing markets for labor and materials. Under SDCL 21-1-11, the plaintiff “is entitled,” and the right to recover was vested in the plaintiff on a particular date, i.e., the date the repair costs were fixed.
The fact that the plaintiff did not treat these damages as certain until late in the game is relevant, but not determinative. Likewise, the fact that the jury verdict did not treat them as such is not the issue under the statute. The right to prejudgment interest under SDCL 21-1-11 is not determined by the amount claimed in the complaint, the amended complaint, or even the amount determined in the verdict. It is a question of whether the proof reflects the elements of SDCL 21-1-11. If the proof does, then the court should mathematically compute the prejudgment interest.
Here, prejudgment interest was required because it was certain or capable of being made certain by calculation and the right to recover was vested in the plaintiff on a particular date. Interest is allowed on damages if there exists established or reasonably ascertainable market prices or values on the subject matter, by reference to which the amount due may be determined by computation. Amert v. Ziebarth Constr. Co., 400 N.W.2d 888 (S.D.1987); Barton Masonry, Inc. v. Varilek, 375 N.W.2d 200 (S.D.1985); Dougherty v. Beckman, 347 N.W.2d 587 (S.D.1984); Beka v. Lithium Corp. of America, 77 S.D. 370, 92 N.W.2d 156 (1958). Where the amount sought, even though unliquidated, is based upon the readily ascertainable value of services or property, the general rule is to allow interest in the absence of strong equities to the contrary. Amert, supra; Aetna Casualty and Surety Co. v. United States, 365 F.2d 997 (8th Cir.1966). Prejudgment interest should be allowed even where there is an offset, counterclaim or claim of contributory negligence. I submit this is the clear intent of SDCL 21-1-11 for claims arising from contract, such as we have here. SDCL 21-1-11 does not say that every person is entitled to prejudgment interest, unless there is an offset, *28counterclaim or claim of contributory negligence. The statute specifies two, and only two, exceptions, i.e., where debtor prevented by 1) law, or 2) creditor from paying the debt.
The majority opinion purports to deny prejudgment interest because a “contributory negligence” claim “makes it impossible for a defendant to reasonably know what it should pay a plaintiff. As stated in Amert, the defendant should not be able to avail himself of this argument unless he in fact has tendered payment or made an offer of payment. The language of the statute provides, “except during such time as the debtor is prevented by law, or by the act of the creditor, from paying the debt.” In this case, the debtor does not even claim that he was prevented by law, or by the act of the creditor, from paying the debt. In fact, he has continually and vigorously persisted in his right to resist the debt. Obviously, a debtor has the right to resist the debt, but in the meantime, he has had the use of the money and should pay interest on the obligation in accordance with SDCL 21-1-11, Meyer v. Dixon Brothers, Inc., 369 N.W.2d 658 (S.D.1985), Amert, supra, and others.
The reference in SDCL 21-1-11 is to the right to recover upon a particular day. As soon as damages are certain or capable of being made certain by calculation by reference to prevailing markets for labor and materials, then damages are vested and interest begins to run. Interest should be awarded from the date each item of expense was incurred. The trial court denied prejudgment interest because it believed it could not ascertain a definite date when interest began to accrue. There may have been some difficulty, but it was certainly possible here. The only time there is a tolling of the reasonable period before interest runs is if the debtor tried to pay and the creditor refused to accept. SDCL 21-1-11. As stated above, it is a question of whether the proof reflects the elements of SDCL 21-1-11. If the proof does, and it does in this case, then the court should mathematically compute the prejudgment interest.
In summary, plaintiff sued in contract, and in negligence. Plaintiffs damages are supported in contract, and in negligence. To the extent that the defendant’s contributory negligence claim was successful, both damages and prejudgment interest on those damages have already been denied. To deny prejudgment interest a second time on sustainable damages is contrary to the letter and the spirit of SDCL 21-1-11. Much of this difficulty and fuss would not exist if the prejudgment interest rate were 1) reasonable, and 2) either lower or the same as the post-judgment interest rate. Legislative common sense is lacking where the pre judgment interest rate is 3% higher than the post -judgment interest. See SDCL §§ 54-3-4 and 54-3-5 (prejudgment interest), 54-3-5.1 (post-judgment interest), and 54-3-16 (state interest rates).
I am authorized to state that MORGAN, J., joins in this concurrence in part and dissent in part.