Millicom International Cellular (TIGO) had the highest return between 1999 and 2003 by a US stock with a market cap of $1B+, returning 6,921.1%.

ASSET	YEARS	% RETURN
Millicom International Cellular (TIGO)	1999-2003	6,921.12%
Companhia Siderurgica Nacional ADR (SID)	1999-2003	1,755.47%
FTI Consulting (FCN)	1999-2003	1,487.42%
SSR Mining (SSRM)	1999-2003	1,222.64%
Axon Enterprise (AXON)	1999-2003	1,076.79%
Laboratory Corporation of America (LH)	1999-2003	975%
Perdoceo Education (PRDO)	1999-2003	960.11%
Meritage (MTH)	1999-2003	955.68%
Middleby (MIDD)	1999-2003	937.33%
Hovnanian Enterprises (HOV)	1999-2003	916.76%
NVR (NVR)	1999-2003	877.2%
Deckers Outdoor (DECK)	1999-2003	864.35%
Merit Medical Systems (MMSI)	1999-2003	851.28%
Hudbay Minerals (HBM)	1999-2003	824.98%
Light & Wonder (LNW)	1999-2003	805.07%
Cognizant Technology Solutions Corp Class A (CTSH)	1999-2003	794.2%
Cal-Maine Foods (CALM)	1999-2003	789.87%
Braskem SA Class A (BAK)	1999-2003	758.99%
Integra LifeSciences (IART)	1999-2003	749.17%
Inter Parfums (IPAR)	1999-2003	742.98%
Hope Bancorp (HOPE)	1999-2003	738%
Diodes (DIOD)	1999-2003	734.18%
Qualcomm (QCOM)	1999-2003	728.02%
Quest Diagnostics (DGX)	1999-2003	723.79%
Gerdau SA ADR (GGB)	1999-2003	710.44%