First Solar (FSLR) had the highest return between 2006 and 2007 by a large-cap US stock, returning 990.4%.

ASSET	YEARS	% RETURN
First Solar (FSLR)	2006-2007	990.37%
CF Industries (CF)	2006-2007	626.21%
Baidu (BIDU)	2006-2007	506.69%
Deckers Outdoor (DECK)	2006-2007	444.25%
Mastercard (MA)	2006-2007	436.89%
Intercontinental Exchange (ICE)	2006-2007	427.4%
Booking (BKNG)	2006-2007	414.62%
Illumina (ILMN)	2006-2007	315.86%
Trip Group Ltd ADR (TCOM)	2006-2007	296.17%
Hudbay Minerals (HBM)	2006-2007	277.36%
Southern Copper (SCCO)	2006-2007	274.92%
Credicorp (BAP)	2006-2007	260.21%
CNH Industrial (CNH)	2006-2007	255.02%
Steel Dynamics (STLD)	2006-2007	241.79%
Petroleo Brasileiro Petrobras SA ADR (PBR)	2006-2007	239%
Ambev SA ADR (ABEV)	2006-2007	238.62%
MercadoLibre (MELI)	2006-2007	235.82%
ArcelorMittal SA ADR (MT)	2006-2007	229.21%
Biomarin Pharmaceutical (BMRN)	2006-2007	229%
Chipotle Mexican Grill (CMG)	2006-2007	226.82%
POSCO (PKX)	2006-2007	223.07%
Vale SA ADR (VALE)	2006-2007	221.5%
Suzano Papel e Celulose SA ADR (SUZ)	2006-2007	213.37%
ICON (ICLR)	2006-2007	201.1%
Garmin (GRMN)	2006-2007	195.05%

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