Ally Fin., Inc. v. Stevenson, 430 P.3d 522

Stevenson bought a new Jayco fifth-wheel RV from Big Sky RV in 2014, financed by Ally; within two months it required extensive repairs (41-item work order) including unsafe tires and was repaired by a dealer.
Stevenson stopped payments to Ally; Ally sued for possession and obtained partial summary judgment on some claims (not challenged here). Stevenson filed counterclaims against Ally and third-party claims against Big Sky RV (breach, bad faith, negligence, Montana Consumer Protection Act, punitive damages).
Big Sky RV moved for judgment on the pleadings (denied); it filed an interlocutory appeal on jurisdiction/venue; Ally later moved for summary judgment and obtained partial summary judgment against Stevenson.
Stevenson sought leave (within the court’s scheduling deadline) to amend her third-party pleading to drop certain claims/parties and add a misrepresentation claim against Big Sky RV; the District Court denied the motion as unduly prejudicial and futile.
The District Court then entered judgment in favor of Big Sky RV (despite Big Sky RV never moving for summary judgment); the Montana Supreme Court reversed the denial to amend and vacated the judgment for Big Sky RV, remanding for further proceedings.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether district court abused discretion by denying leave to amend third-party complaint	Stevenson: amendment was timely (within scheduling deadline), clarified claims, removed parties, and misrepresentation arises from same factual allegations	Big Sky RV: amendment introduced new legal theory after long delay and after Ally moved for summary judgment, causing undue prejudice and wasted effort	Reversed: denial was an abuse of discretion; amendment was not unduly prejudicial or futile
Whether entry of judgment for Big Sky RV was proper	Stevenson: judgment erroneous because Big Sky RV never moved for summary judgment and Ally’s partial summary judgment did not resolve claims against Big Sky RV	Big Sky RV: relied on District Court’s partial grant to Ally as basis for judgment	Reversed: entry of judgment for Big Sky RV was erroneous and is vacated

Farmers Coop. Ass'n v. Amsden, 339 Mont. 445, 171 P.3d 690 (rule 15(a) amendments; undue prejudice test)
Allison v. Town of Clyde Park, 302 Mont. 55, 11 P.3d 544 (liberal allowance of amendments)
Bitterroot Int'l Sys. v. Western Star Trucks, Inc., 336 Mont. 145, 153 P.3d 627 (factors for undue prejudice and delay)
Peuse v. Malkuch, 275 Mont. 221, 911 P.2d 1153 (relief when opposing party has already moved for summary judgment)
Haugen Trust v. Warner, 204 Mont. 508, 665 P.2d 1132 (amendments to correct mistakes should be freely given when not prejudicial)
Hobble-Diamond Cattle Co. v. Triangle Irrigation Co., 249 Mont. 322, 815 P.2d 1153 (futility as a basis to deny amendment)
Rolan v. New W. Health Servs., 389 Mont. 228, 405 P.3d 65 (balancing prejudice vs. justification for delay)