NRG Energy (NRG) had the highest return in July 2017 by a US stock in the S&P 500 (GSPC), returning 42.2%.

ASSET	MONTH	% RETURN
NRG Energy (NRG)	July 2017	42.16%
First Solar (FSLR)	July 2017	23.52%
Boeing (BA)	July 2017	22.41%
Netflix (NFLX)	July 2017	21.27%
Freeport-McMoran Copper & Gold (FCX)	July 2017	21.03%
Vertex Pharmaceuticals (VRTX)	July 2017	17.24%
Newmont Goldcorp (NEM)	July 2017	16.96%
Automatic Data Processing (ADP)	July 2017	16.6%
Charter Communications (CHTR)	July 2017	15.88%
Teradyne (TER)	July 2017	14.65%
Texas Pacific Land Trust (TPL)	July 2017	13.57%
Ameriprise Financial (AMP)	July 2017	12.71%
NVIDIA (NVDA)	July 2017	12.04%
Lam Research (LRCX)	July 2017	11.74%
Facebook (META)	July 2017	11.55%
Align Technology (ALGN)	July 2017	10.7%
Huntington Ingalls Industries (HII)	July 2017	10.6%
T Rowe Price (TROW)	July 2017	10.51%
Verizon Communications (VZ)	July 2017	9.92%
Cadence Design Systems (CDNS)	July 2017	9.89%
Electronic Arts (EA)	July 2017	9.6%
Autodesk (ADSK)	July 2017	9.35%
BorgWarner (BWA)	July 2017	9.21%
FirstEnergy (FE)	July 2017	9.13%
Howmet Aerospace (HWM)	July 2017	9.02%