Prejudgment Interest Rules in New Mexico
At a glance
| Governing law | NMSA 1978 § 56-8-3 supplies the default rate categories for contract money, retained money, and matured accounts; § 56-8-4(B) supplies the general discretionary prejudgment route; § 41-4-19(C)-(D) governs interest on covered government tort judgments |
|---|---|
| Interest rate | Section 56-8-3: not more than 15% per year absent a written contract fixing a different rate. Section 56-8-4(B): up to 10%, selected by the court |
| When interest starts running | Section 56-8-4(B): service of the complaint. Section 56-8-3(C): matured-account interest from the day the balance is ascertained; § 56-8-3 states no single express start date for its other two categories |
| Contract vs. tort claims | Section 56-8-3 specifically covers money due by contract and two other listed money categories. Section 56-8-4(B) is a separate discretionary judgment-based route not textually limited to contract or tort |
| Mandatory or discretionary | Section 56-8-4(B) is expressly discretionary and permits up to 10% after listed considerations. Section 56-8-3 sets eligible categories and a rate ceiling but does not itself state a general court/jury discretion standard |
| Simple or compound | No prejudgment compounding method is stated in §§ 56-8-3 or 56-8-4(B); both express rates per year, and the cell does not assume interest-on-interest without separate authority |
| Claims against the government | For a tort with immunity waived under the Tort Claims Act, § 41-4-19(D) bars interest before judgment; subsection (C) instead supplies postjudgment interest at 2 points above prime, computed daily from judgment entry |
| Other exceptions | Section 56-8-4(B) does not apply to unpaid-child-support judgments; § 56-8-4(C) preserves interest otherwise permitted by statute or common law; written-contract rates displace § 56-8-3's default ceiling |
Requirements one by one
Governing law
New Mexico has two different statutory paths. NMSA 1978 § 56-8-3 addresses money due by contract, money held for another without consent, and matured-account balances. Section 56-8-4(B) separately gives the court discretion to add prejudgment interest to a judgment after considering litigation delay and settlement conduct. Covered government tort judgments use § 41-4-19 instead.
Interest rate
Section 56-8-3 sets a ceiling of 15% per year when no written contract fixes a different rate. Section 56-8-4(B) allows the court to choose a rate up to 10%. Do not confuse those prejudgment figures with § 56-8-4(A)'s post-entry judgment rates of 8.75% ordinarily and 15% for a judgment based on tortious conduct, bad faith, or intentional or willful acts.
When interest starts running
The discretionary § 56-8-4(B) route starts no earlier than service of the complaint. Section 56-8-3(C) expressly starts matured-account interest on the day the balance is ascertained. The text of § 56-8-3 does not print one universal start date for money due by contract or money retained without consent, so those categories require the applicable facts and any controlling authority beyond the quoted sentence.
Contract vs. tort claims
Section 56-8-3 expressly includes money due by contract but does not mention tort damages. Section 56-8-4(B) is phrased around the judgment rather than the cause of action and does not state a contract-versus-tort limitation. Its discretionary route therefore should not be described as a tort-only statute, even though tort claims may commonly rely on it.
Mandatory or discretionary
Section 56-8-4(B) is explicit: the court "in its discretion may allow" up to 10% after considering, among other things, whether the plaintiff caused unreasonable delay and whether the defendant made a reasonable and timely settlement offer. Section 56-8-3 states the listed claim categories and rate ceiling, but the current sentence does not itself spell out a separate discretionary standard or decision maker.
Simple or compound
Neither § 56-8-3 nor § 56-8-4(B) states that ordinary civil prejudgment interest compounds or supplies a compounding interval. Both express annual rates. Without separate controlling authority, the statutory text alone does not support adding interest on accumulated prejudgment interest.
Claims against the government
Section 56-8-4(D) exempts the State and its political subdivisions from that section unless another statute or common law provides otherwise. The Tort Claims Act is specific: § 41-4-19(D) bars interest before judgment on a covered waived-immunity tort claim. Subsection (C) then allows postjudgment interest at two percentage points above the published prime rate on judgment-entry day, computed daily until payment.
Other exceptions
The discretionary § 56-8-4(B) route excludes a judgment based on unpaid child support. Section 56-8-4(C) preserves awards and timing permitted elsewhere by statute or common law. A written contract fixing a different rate also takes the claim outside § 56-8-3's default rate ceiling.
What trips people up
The three percentages do different jobs. Fifteen percent is the ceiling in § 56-8-3 when no written contract fixes another rate, and it is also the elevated postjudgment rate in § 56-8-4(A)(2). The general discretionary prejudgment ceiling in § 56-8-4(B) is 10%, not 15%.
The government rule is also easy to invert. Section 41-4-19(C) does allow interest on a covered government tort judgment, but only from judgment entry forward. Subsection (D) expressly bars interest prior to judgment.
Common questions
Does interest always run from the breach date? Not under the discretionary statute: § 56-8-4(B) starts from service of the complaint. Section 56-8-3(C) separately uses the day a matured-account balance is ascertained.
Does a settlement offer matter? Yes. Under § 56-8-4(B), a reasonable and timely defense offer is one of the factors the court considers, along with plaintiff-caused delay.
Can the court award more than 10% under § 56-8-4(B)? No. That subsection's discretionary prejudgment ceiling is 10%, even though other parts of New Mexico's interest statutes use 15% for different purposes.
Statutes and sources
- NMSA 1978 §§ 56-8-3 and 56-8-4 — https://nmonesource.com/nmos/nmsa/en/4418/1/document.do (accessed 2026-08-16)
- NMSA 1978 § 41-4-19(C)-(D) — https://nmonesource.com/nmos/nmsa/en/4382/1/document.do (accessed 2026-08-16)
Source links
Every statute quoted above, linked, with the date we checked it.
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