Insmed (INSM) had the highest return between 1999 and 2001 by a large-cap US stock, returning 90,421.3%.

ASSET	YEARS	% RETURN
Insmed (INSM)	1999-2001	90,421.33%
NVIDIA (NVDA)	1999-2001	1,174.56%
Laboratory Corporation of America (LH)	1999-2001	1,076.1%
Suzano Papel e Celulose SA ADR (SUZ)	1999-2001	1,068.34%
Biogen (BIIB)	1999-2001	778.78%
Quest Diagnostics (DGX)	1999-2001	708.01%
Qualcomm (QCOM)	1999-2001	670.44%
Neurocrine Biosciences (NBIX)	1999-2001	633%
Logitech International (LOGI)	1999-2001	501.7%
Check Point Software Technologies (CHKP)	1999-2001	420.3%
CACI International (CACI)	1999-2001	369.77%
Copart (CPRT)	1999-2001	347.06%
Coherent (COHR)	1999-2001	330.75%
NVR (NVR)	1999-2001	327.79%
Pool (POOL)	1999-2001	308.34%
Enterprise Products Partners (EPD)	1999-2001	303.33%
Regeneron Pharmaceuticals (REGN)	1999-2001	302.29%
Lam Research (LRCX)	1999-2001	284.33%
Infosys Ltd ADR (INFY)	1999-2001	236.29%
Arthur J Gallagher (AJG)	1999-2001	235.98%
Ryanair Holdings PLC ADR (RYAAY)	1999-2001	235.17%
Celestica (CLS)	1999-2001	225.56%
UnitedHealth (UNH)	1999-2001	224.05%
Brown & Brown (BRO)	1999-2001	222.26%
Gilead Sciences (GILD)	1999-2001	220.59%

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