Kraft Heinz (KHC) had the highest return in March 2015 by a large-cap US stock, returning 35.8%.

ASSET	MONTH	% RETURN
Kraft Heinz (KHC)	March 2015	35.8%
Trip Group Ltd ADR (TCOM)	March 2015	31.11%
Summit Therapeutics (SMMT)	March 2015	25.15%
RBC Bearings (RBC)	March 2015	23.47%
Biomarin Pharmaceutical (BMRN)	March 2015	16.47%
Centene (CNC)	March 2015	15.11%
Cooper Companies, Inc Common Stock (COO)	March 2015	14.04%
Novo Nordisk A-S (NVO)	March 2015	13.83%
Comfort Systems USA (FIX)	March 2015	13.29%
CBRE Group Inc Class A (CBRE)	March 2015	12.73%
Elbit Systems (ESLT)	March 2015	12.18%
United Therapeutics (UTHR)	March 2015	11.43%
ResMed (RMD)	March 2015	11.43%
Skyworks Solutions (SWKS)	March 2015	11.39%
Builders FirstSource (BLDR)	March 2015	10.98%
CoreSite Realty (COR)	March 2015	10.82%
Steel Dynamics (STLD)	March 2015	10.6%
Grupo Financiero Galicia SA ADR (GGAL)	March 2015	10.45%
Insmed (INSM)	March 2015	10.34%
Owens Corning (OC)	March 2015	10.12%
West Pharmaceutical Services (WST)	March 2015	10.01%
Rollins (ROL)	March 2015	9.98%
American Airlines (AAL)	March 2015	9.5%
Teva Pharma Industries Ltd ADR (TEVA)	March 2015	9.36%
Quest Diagnostics (DGX)	March 2015	9.33%

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