Exelixis (EXEL) had the highest return in Q3 2015 by a large-cap US stock, returning 55.8%.

ASSET	QUARTER	% RETURN
Exelixis (EXEL)	Q3 2015	55.83%
Coca-Cola Consolidated (COKE)	Q3 2015	29.34%
Grupo Aeroportuario del Pacifico SAB De CV ADR (PAC)	Q3 2015	28.43%
NVIDIA (NVDA)	Q3 2015	20.11%
Infosys Ltd ADR (INFY)	Q3 2015	19.46%
Chipotle Mexican Grill (CMG)	Q3 2015	18.79%
Motorola Solutions (MSI)	Q3 2015	18.75%
Molson Coors Brewing (TAP)	Q3 2015	18.7%
CDW (CDW)	Q3 2015	18.23%
Comfort Systems USA (FIX)	Q3 2015	18.08%
Alphabet Inc Class A (GOOGL)	Q3 2015	17.42%
Cboe Global Markets (CBOE)	Q3 2015	17.27%
Assurant (AIZ)	Q3 2015	16.87%
Consolidated Edison (ED)	Q3 2015	16.76%
Amazon (AMZN)	Q3 2015	16.51%
WEC Energy (WEC)	Q3 2015	16.25%
Synnex (SNX)	Q3 2015	15.81%
Dr Reddy’s Laboratories Ltd ADR (RDY)	Q3 2015	15.33%
MicroStrategy (MSTR)	Q3 2015	14.75%
Tyler Technologies (TYL)	Q3 2015	14.48%
IDEXX Laboratories (IDXX)	Q3 2015	14.28%
Atmos Energy (ATO)	Q3 2015	14.07%
Edison International (EIX)	Q3 2015	13.89%
American Water Works (AWK)	Q3 2015	13.69%
Pinnacle West Capital (PNW)	Q3 2015	13.57%

Large-cap stocks are treated as having a market cap of $10B+.