Cindy Castillo v. Bank of America, Na, 980 F.3d 723

Plaintiff Castillo worked at a Bank of America (BOA) California call center; BOA employed ~5,031 hourly non‑managerial call‑center employees during the class period.
BOA paid flat‑sum nondiscretionary monthly incentives ($350–$2,100) and, when employees earned a bonus and worked overtime, BOA calculated overtime by allocating the bonus across hours using a divisor that included total hours worked.
BOA used two different formulaic methods in two time periods (different ways of dividing bonuses and allocating to overtime hours), but both used total hours in the divisor.
Castillo sued for unpaid overtime (among other claims) and moved to certify a class on the overtime claim; the district court found commonality and typicality but denied certification for lack of predominance.
The Ninth Circuit affirmed: commonality and typicality satisfied, but predominance was not because many putative class members were never exposed to the challenged formulas or were not injured by them, and Castillo lacked a common method to prove classwide liability.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Commonality	Single common legal question: whether BOA's use of total hours in the divisor is unlawful	Two different policies over different periods defeat a single common question	Commonality satisfied; a classwide legal question exists
Typicality	Castillo received bonuses and worked overtime so her claim is representative	Castillo relied on an improper supplemental expert; exposure varies by period	Typicality satisfied; Castillo's injuries were reasonably co‑extensive with class
Predominance (23(b)(3))	Alvarado and common legal issues make liability classwide; damages can be individualized later	Large subset never worked overtime or never received bonuses; liability requires individualized proof	Predominance not satisfied; many members not exposed or injured so individualized liability inquiries predominate
Method of proof / representative evidence	Can rely on representative or common proof (analogous to Tyson Foods) to show classwide liability	No common representative proof of exposure/underpayment; cannot prove fact of injury classwide	No adequate common method of proof; unlike Tyson Foods, Castillo offered no reliable classwide evidence of injury

Alvarado v. Dart Container Corp. of Cal., 411 P.3d 528 (Cal. 2018) (California Supreme Court held flat‑sum bonuses must be apportioned using non‑overtime hours in the divisor)
Vaquero v. Ashley Furniture Indus., Inc., 824 F.3d 1150 (9th Cir. 2016) (individualized damages calculations do not defeat predominance if liability can be resolved classwide)
Tyson Foods, Inc. v. Bouaphakeo, 136 S. Ct. 1036 (U.S. 2016) (representative/ statistical evidence can, in some circumstances, establish classwide liability)
Amgen Inc. v. Conn. Ret. Plans & Trust Funds, 568 U.S. 455 (U.S. 2013) (predominance requires a class be sufficiently cohesive for adjudication by representation)
Torres v. Mercer Canyons Inc., 835 F.3d 1125 (9th Cir. 2016) (class must not include many members who could not have been harmed by the challenged conduct)
Wal‑Mart Stores, Inc. v. Dukes, 564 U.S. 338 (U.S. 2011) (commonality requires a common contention capable of classwide resolution)