Downs v. Homax Oil Sales, Inc., 421 P.3d 518

Homax sued Downs for tortious interference after RKI terminated fuel purchases from Homax following a trespass incident and a report by Downs’ daughter. Downs counterclaimed for trespass. The district court held a bench trial and awarded Homax $250,000.
During discovery Homax produced a one‑page document showing gross revenue from RKI for 2014–2015 but did not provide a damages computation or supporting expense documents required by W.R.C.P. 26.
On the first day of trial Homax tendered a paper exhibit folder that included an expanded three‑page Exhibit 4 (two additional pages showing monthly gross profit tables) that had not been previously produced; defense counsel inadvertently stipulated to the exhibits without knowing about the extra pages.
Homax’s only damages testimony came from its president, who (a) testified to net lost profits ($330,000 total; $176,000/year estimate) based on applying a blanket net‑margin percentage from the company’s overall operation, and (b) relied on undisclosed spreadsheets and unspecified “associated expenses.”
Downs objected that Homax failed to disclose its damages computation and supporting documents; the district court admitted the damages evidence and awarded ten months of damages at $25,000/month. Downs appealed.

Issue	Homax's Argument	Downs' Argument	Held
Whether the district court abused its discretion by admitting Homax's damages evidence given Rule 26 disclosures	Homax implied the expanded exhibit and testimony were harmless or effectively disclosed (and relied on the stipulation)	Homax failed to disclose damages computation and supporting documents as required by Rule 26, so evidence should be excluded under Rule 37(c)(1)	Court: Homax violated Rule 26; failed to show justification or harmlessness; admission of damages evidence was an abuse of discretion and should have been excluded
Whether the damages award was supported by the evidence	The district court relied on Exhibit 4 and Homax’s testimony to award $25,000/month	Damages for tortious interference are net lost profits; Homax’s proof was based on gross figures and a generalized net‑margin percentage without prorated expenses or reasonable certainty	Court: Award was clearly erroneous; net lost profit evidence failed reasonable‑certainty standard; judgment reversed and entry for Downs directed

Dishman v. First Interstate Bank, 362 P.3d 360 (Wyo. 2015) (Rule 26(a) requires disclosure of damages computation and supporting documents; Rule 37(c)(1) can mandate automatic exclusion unless justified or harmless)
Hopper v. All Pet Animal Clinic, Inc., 861 P.2d 531 (Wyo. 1993) (net lost profits must be calculated by deducting business expenses; proof requires reasonable certainty and prorating of expenses)
Exotex Corp. v. Rinehart, 3 P.3d 826 (Wyo. 2000) (lost profits are recoverable for tortious interference and represent expected gains minus necessary costs)
Ahrenholtz v. Laramie Economic Development Corp., 79 P.3d 511 (Wyo. 2003) (adopts Restatement formulation of tortious interference elements)
Jackman Constr., Inc. v. Rock Springs Winnelson Co., 385 P.3d 311 (Wyo. 2016) (courts generally enforce stipulations but relief may be warranted for mistake or misrepresentation)