Micron Technology (MU) had the highest return in March 2017 by a large-cap US stock, returning 19.6%.

ASSET	MONTH	% RETURN
Micron Technology (MU)	March 2017	19.62%
Coca-Cola Consolidated (COKE)	March 2017	19.36%
Vertex Pharmaceuticals (VRTX)	March 2017	19.12%
Veeva Systems Inc Class A (VEEV)	March 2017	19.09%
Gold Fields Ltd ADR (GFI)	March 2017	17.06%
Amkor Technology (AMKR)	March 2017	16.6%
Banco Bilbao Viscaya Argentaria SA ADR (BBVA)	March 2017	16.39%
Best Buy (BBY)	March 2017	16.38%
YPF Sociedad Anonima (YPF)	March 2017	15.95%
Wynn Resorts (WYNN)	March 2017	14.72%
Lumentum (LITE)	March 2017	14.36%
Canadian Natural Resources (CNQ)	March 2017	13.85%
Alamos Gold (AGI)	March 2017	13.58%
Ferrari (RACE)	March 2017	13.35%
Banco Santander Chile (BSAC)	March 2017	13.18%
Jabil Circuit (JBL)	March 2017	12.53%
Sibanye Gold Ltd ADR (SBSW)	March 2017	12.09%
Deckers Outdoor (DECK)	March 2017	11.67%
Monster Beverage (MNST)	March 2017	11.49%
Grupo Aeroportuario del Pacifico SAB De CV ADR (PAC)	March 2017	11.3%
Logitech International (LOGI)	March 2017	11.24%
America Movil SAB de CV ADR (AMX)	March 2017	11.14%
Nova (NVMI)	March 2017	11.12%
Darden Restaurants (DRI)	March 2017	10.92%
NRG Energy (NRG)	March 2017	10.91%

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