Natwest (NWG) had the highest return between 2005 and 2008 by a large-cap US stock, returning 1,589,066.7%.

ASSET	YEARS	% RETURN
Natwest (NWG)	2005-2008	1,589,066.67%
National Grid PLC ADR (NGG)	2005-2008	824,847.62%
Monster Beverage (MNST)	2005-2008	617.38%
First Solar (FSLR)	2005-2008	463.1%
Illumina (ILMN)	2005-2008	453.08%
Clean Harbors (CLH)	2005-2008	317.37%
Sociedad Quimica y Minera de Chile SA ADR B (SQM)	2005-2008	298.28%
Banco Bradesco SA ADR (BBD)	2005-2008	290.3%
Agnico Eagle Mines (AEM)	2005-2008	279.71%
Credicorp (BAP)	2005-2008	259.83%
Mastercard (MA)	2005-2008	257.63%
Stifel Financial (SF)	2005-2008	230.65%
Alnylam Pharmaceuticals (ALNY)	2005-2008	222.43%
Intuitive Surgical (ISRG)	2005-2008	217.32%
Booking (BKNG)	2005-2008	210.5%
CF Industries (CF)	2005-2008	206.06%
Southern Copper (SCCO)	2005-2008	193.42%
Gilead Sciences (GILD)	2005-2008	187.79%
Suzano Papel e Celulose SA ADR (SUZ)	2005-2008	186.57%
Royal Gold (RGLD)	2005-2008	185.17%
Petroleo Brasileiro Petrobras SA ADR (PBR)	2005-2008	184.22%
Vertex Pharmaceuticals (VRTX)	2005-2008	183.93%
Biomarin Pharmaceutical (BMRN)	2005-2008	178.56%
Kinross Gold (KGC)	2005-2008	166.17%
Petróleo Brasileiro SA - Petrobras (PBR.A)	2005-2008	166.03%

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