QXO (QXO) had the highest return in December 2011 by a large-cap US stock, returning 250%.

ASSET	MONTH	% RETURN
QXO (QXO)	December 2011	250%
Neurocrine Biosciences (NBIX)	December 2011	30.57%
Monolithic Power Systems (MPWR)	December 2011	25.58%
XPO Logistics (XPO)	December 2011	22.4%
Vulcan Materials (VMC)	December 2011	21.9%
Kratos Defense & Security Solutions (KTOS)	December 2011	19.4%
Cemex SAB de CV ADR (CX)	December 2011	17.43%
Targa Resources (TRGP)	December 2011	17.33%
DexCom (DXCM)	December 2011	16.23%
United Therapeutics (UTHR)	December 2011	16.12%
Vertex Pharmaceuticals (VRTX)	December 2011	15.79%
Super Micro Computer (SMCI)	December 2011	15.55%
Alnylam Pharmaceuticals (ALNY)	December 2011	15.44%
Cooper Companies (COO)	December 2011	15.19%
Cintas (CTAS)	December 2011	14.73%
Energy Transfer (ET)	December 2011	14.73%
Nova (NVMI)	December 2011	14.44%
GE Aerospace (GE)	December 2011	13.81%
Leonardo DRS, Inc Common Stock (DRS)	December 2011	13.53%
Takeda Pharmaceutical Co Ltd ADR (TAK)	December 2011	13.37%
SS&C Technologies (SSNC)	December 2011	13.23%
Plains All American Pipeline (PAA)	December 2011	13.02%
Banco Santander Chile (BSAC)	December 2011	12.98%
Canadian Pacific Railway (CP)	December 2011	12.51%
Texas Roadhouse (TXRH)	December 2011	12.14%

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