John Mazor v. Elizabeth Farrell, 186 A.3d 829

Esther Mazor died leaving two trusts (A and B) funded from her residuary estate; funds were not initially placed into the trusts but into an account controlled by her son Julian Mazor.
Julian Mazor used estate funds for himself and his wife Elizabeth Farrell; some estate funds went to purchase and improve a D.C. house and to finance a Cape Cod house (down payment and mortgage payments).
John and William Mazor sued Julian and Farrell for recovery of misappropriated estate funds; Julian defaulted, Farrell contested liability.
The trial court found Farrell liable in unjust enrichment for roughly $320,000 traceable to the Cape Cod house but found her an innocent recipient as to many other expenditures and denied recovery of consequential gains; plaintiffs sought prejudgment interest.
On remand the trial court denied prejudgment interest under D.C. Code § 15-108, concluding the unjust-enrichment claim was not an action to recover a "liquidated debt;" plaintiffs appealed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether unjust-enrichment claim is an "action to recover a liquidated debt" under D.C. Code § 15-108 entitling plaintiffs to prejudgment interest	Mazor brothers: debt was liquidated as amount traceable to estate funds was ascertainable and part of claim was fixed	Farrell: unjust-enrichment liability required equitable assessment (innocent recipient issues), so amount was not an easily ascertainable sum certain	Held: Not liquidated. Unjust-enrichment claim and innocent-recipient complexities made amount not an "easily ascertainable sum certain," so § 15-108 prejudgment interest unavailable.

Steuart Inv. Co. v. The Meyer Grp., 61 A.3d 1227 (D.C. 2013) (defines liquidated debt as an easily ascertainable sum certain)
Schwartz v. Swartz, 723 A.2d 841 (D.C. 1998) (quantum meruit and similar claims are unliquidated)
Aon Risk Servs., Inc. of Wash., D.C. v. Estate of Coyne, 915 A.2d 370 (D.C. 2007) (dispute over proper assessment of damages renders claims unliquidated)
District of Columbia v. Pierce Assocs., 527 A.2d 306 (D.C. 1987) (discussion of liquidated debt rationale and prejudgment interest statutes)
Dist. Cablevision Ltd. P’ship v. Bassin, 828 A.2d 714 (D.C. 2003) (prejudgment interest is remedial and to be generously construed, but statutory requirements limit awards)
Potomac Elec. Power Co. v. District of Columbia, 402 A.2d 430 (D.C. 1979) (prejudgment interest compensates for loss of use of money)
Burke v. Groover, Christie & Merritt, P.C., 26 A.3d 292 (D.C. 2011) (courts may award prejudgment interest in equity even absent statutory authorization)
Falconi-Sachs v. LPF Senate Square, LLC, 142 A.3d 550 (D.C. 2016) (elements of unjust enrichment explained)