CarMax (KMX) had the highest return between 2000 and 2003 by a US stock with a market cap of $3B+, returning 1,274.7%.

ASSET	YEARS	% RETURN
CarMax (KMX)	2000-2003	1,274.67%
Meritage (MTH)	2000-2003	1,133.71%
Axon Enterprise (AXON)	2000-2003	1,076.79%
Amedisys (AMED)	2000-2003	1,002.6%
Cal-Maine Foods (CALM)	2000-2003	964.53%
FTI Consulting (FCN)	2000-2003	951.66%
Millicom International Cellular (TIGO)	2000-2003	941.32%
NVR (NVR)	2000-2003	875.92%
Tractor Supply (TSCO)	2000-2003	870.85%
Companhia Energetica de Minas Gerais CEMIG Pref ADR (CIG)	2000-2003	726.32%
Merit Medical Systems (MMSI)	2000-2003	724.44%
Deckers Outdoor (DECK)	2000-2003	681.14%
Tapestry (TPR)	2000-2003	655.03%
Middleby (MIDD)	2000-2003	645.93%
Clean Harbors (CLH)	2000-2003	631.05%
Frontline (FRO)	2000-2003	612.69%
International Game Technology (IGT)	2000-2003	607.37%
Lennar (LEN)	2000-2003	559.72%
Altria (MO)	2000-2003	559.6%
RadNet (RDNT)	2000-2003	558.82%
Comstock Resources (CRK)	2000-2003	557.02%
Royal Gold (RGLD)	2000-2003	502.69%
DR Horton (DHI)	2000-2003	491.85%
DaVita HealthCare Partners (DVA)	2000-2003	477.78%
Inter Parfums (IPAR)	2000-2003	471.7%