Natwest (NWG) had the highest return between 2006 and 2007 by a large-cap US stock, returning 15,058,300%.

ASSET	YEARS	% RETURN
Natwest (NWG)	2006-2007	15,058,300%
First Solar (FSLR)	2006-2007	990.37%
CF Industries (CF)	2006-2007	626.21%
Mosaic (MOS)	2006-2007	544.4%
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	414.6%
Illumina (ILMN)	2006-2007	315.86%
Trip Group Ltd ADR (TCOM)	2006-2007	296.17%
GameStop (GME)	2006-2007	290.39%
Southern Copper (SCCO)	2006-2007	274.98%
Credicorp (BAP)	2006-2007	260.21%
CNH Industrial (CNH)	2006-2007	255.01%
Steel Dynamics (STLD)	2006-2007	241.78%
Petroleo Brasileiro Petrobras SA ADR (PBR)	2006-2007	239%
Ambev SA ADR (ABEV)	2006-2007	238.54%
MercadoLibre (MELI)	2006-2007	235.82%
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	221.49%
Petróleo Brasileiro SA - Petrobras (PBR.A)	2006-2007	216.32%
ArcelorMittal SA ADR (MT)	2006-2007	215.53%

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