Monster Beverage (MNST) had the highest return in March 2006 by a US stock in the S&P 500 (GSPC), returning 35%.

ASSET	MONTH	% RETURN
Monster Beverage (MNST)	March 2006	34.96%
Intuitive Surgical (ISRG)	March 2006	31.67%
Skyworks Solutions (SWKS)	March 2006	28.65%
Intercontinental Exchange (ICE)	March 2006	25.55%
Steel Dynamics (STLD)	March 2006	23.68%
Akamai Technologies (AKAM)	March 2006	23.46%
Nucor (NUE)	March 2006	22.01%
Chipotle Mexican Grill (CMG)	March 2006	21.36%
NVIDIA (NVDA)	March 2006	21.06%
Take-Two Interactive Software (TTWO)	March 2006	20.23%
Freeport-McMoran Copper & Gold (FCX)	March 2006	19.24%
Molina Healthcare (MOH)	March 2006	17.23%
Quanta Services (PWR)	March 2006	17.02%
MGM Resorts International (MGM)	March 2006	16.84%
DexCom (DXCM)	March 2006	16.23%
CBRE Group Inc Class A (CBRE)	March 2006	15.81%
Hologic (HOLX)	March 2006	15.72%
Wynn Resorts (WYNN)	March 2006	15.69%
Deckers Outdoor (DECK)	March 2006	14.55%
Garmin (GRMN)	March 2006	14.42%
TKO (TKO)	March 2006	14.29%
Smith AO (AOS)	March 2006	13.67%
EMCOR (EME)	March 2006	13.28%
United Airlines (UAL)	March 2006	13.24%
Jabil Circuit (JBL)	March 2006	13.09%