Exelixis (EXEL) had the highest return in July 2015 by a large-cap US stock, returning 59.2%.

ASSET	MONTH	% RETURN
Exelixis (EXEL)	July 2015	59.17%
Chipotle Mexican Grill (CMG)	July 2015	22.42%
Amazon (AMZN)	July 2015	22.03%
Frontline (FRO)	July 2015	21.18%
Alphabet Inc Class A (GOOGL)	July 2015	20.94%
Netflix (NFLX)	July 2015	20.57%
Comfort Systems USA (FIX)	July 2015	19.45%
ICON (ICLR)	July 2015	19.28%
MicroStrategy (MSTR)	July 2015	19.06%
TKO (TKO)	July 2015	17.96%
Summit Therapeutics (SMMT)	July 2015	17.73%
Coca-Cola Europacific Partners (CCEP)	July 2015	16.38%
Teva Pharma Industries Ltd ADR (TEVA)	July 2015	16.2%
Grupo Aeroportuario del Pacifico SAB De CV ADR (PAC)	July 2015	15.02%
Monster Beverage (MNST)	July 2015	14.29%
Fortinet (FTNT)	July 2015	14.1%
Amgen (AMGN)	July 2015	13.97%
Celestica (CLS)	July 2015	13.97%
Take-Two Interactive Software (TTWO)	July 2015	13.92%
VeriSign (VRSN)	July 2015	13.7%
Ascendis Pharma A-S (ASND)	July 2015	13.16%
HF Sinclair (DINO)	July 2015	12.6%
Somnigroup International (SGI)	July 2015	12.46%
Royal Caribbean Cruises (RCL)	July 2015	12.37%
IDEXX Laboratories (IDXX)	July 2015	11.94%

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