The law on pre-judgment interest is that it is to be awarded where there is an agreement for payment of interest or under mercantile custom or under principle of equity, as in breach of fiduciary duty. In all such cases the law is that pre-judgment interest is as of right. The Appellant is no doubt a licensed Commercial Bank and thus bound by its trade custom to give interest on money lodged with it. The law requires a person claiming such right to pre-judgment interest to so plead and prove at the trial. In law generally the Courts have the power to award post-judgment interest but not pre-judgment interest since pre-judgment interest which must be based on pleadings and proof by the party so claiming entitlement to it save if it is part of the mercantile custom of the transaction involving the parties. In all therefore, it is never granted as of course, but must either be part of the contemplation of the parties by virtue of their contract terms or mercantile custom of fiduciary duty or it is specifically pleaded and proved. In Ferrero and Company Ltd. v. Henkel Chemicals Nigeria Ltd. (2011) LPELR 12 (SC). His Lordship, Onnoghen, JSC (as he then was, now CJN) had expatiated on the rationale behind this principle of law inter alia thus: It follows that before a party can claim pre-judgment interest, he has to plead not only his entitlement to the interest but the basis of the entitlement either by Statute or contract/agreement between the parties, or mercantile custom or principle of equity, such as breach of fiduciary relationship. It is not for the Court to speculate or conjecture or assume the facts relevant to the claim. The relevant facts must be pleaded, as fact not pleaded goes to no issue. In addition to the requirement of pleading the relevant facts, the Plaintiff must adduce evidence at the trial in proof of the relevant facts. Where there is no evidence in proof of the facts, then the pleadings are deemed abandoned. See also UBA Plc. v. Oranuba (2013) LPELR- 20692 (CA). See also Hausa v. FBN Plc (2000) 9 NWLR (Pt. 671) 64; Ekwunife v. Wayne W/A Ltd (1989) NWLR (Pt. 122) 422: Hinma Merchant Ltd v. Alhaji Inuwa Aliyu (1994) 5 NWLR (Pt. 347) 667 @ pp. 676-677; Stabilini Visinoni Ltd v. Metalum Ltd. (2007) LPELR-8661 (CA) UBN Ltd v. Salami (1998) 3 NWLR (Pt. 538) 347: Idakula v. Richards (2000) FWLR (Pt. 14) 2439; Jallco Ltd. v. Owoniboys Tech Serv. Ltd. (1995) 4 NWLR (Pt. 391) 534 @ p. 550; Petgas Resources Ltd. v. Louts N. Mbanefo (2007) 6 NWLR (Pt. 1031) 545 @ p. 549; Consolidated Resources Limited v. Abofar Ventures Nigeria Limited (2007) 6 NWLR (pt. 1030) 225.
— B.A. Georgewill JCA. Stanbic IBTC Bank Plc V. Longterm Global Capital Limited & Ors. (CA/L/427/2016, 9 Mar 2018)