Tesla (TSLA) had the lowest return in July 2010 by a US stock in the S&P 500 (GSPC), returning -20.2%.

ASSET	MONTH	% RETURN
Tesla (TSLA)	July 2010	-20.24%
Cboe Global Markets (CBOE)	July 2010	-17.52%
Micron Technology (MU)	July 2010	-14.45%
Western Digital (WDC)	July 2010	-12.33%
Live Nation Entertainment (LYV)	July 2010	-12.1%
Builders FirstSource (BLDR)	July 2010	-10.83%
NVIDIA (NVDA)	July 2010	-10.27%
Charles River Laboratories (CRL)	July 2010	-8.83%
Thermo Fisher Scientific (TMO)	July 2010	-8.54%
Newmont Goldcorp (NEM)	July 2010	-8.44%
DaVita HealthCare Partners (DVA)	July 2010	-8.33%
Intercontinental Exchange (ICE)	July 2010	-7.04%
Stryker (SYK)	July 2010	-6.49%
McKesson (MCK)	July 2010	-6.24%
Universal Health Services (UHS)	July 2010	-6.23%
Genesis Healthcare (GEN)	July 2010	-6.15%
Valero Energy (VLO)	July 2010	-5.77%
Netflix (NFLX)	July 2010	-5.74%
Revvity (RVTY)	July 2010	-5.6%
Akamai Technologies (AKAM)	July 2010	-5.45%
Truist Financial (TFC)	July 2010	-5.27%
CoreSite Realty (COR)	July 2010	-5.25%
Quest Diagnostics (DGX)	July 2010	-5.05%
Masco (MAS)	July 2010	-4.99%
NVR (NVR)	July 2010	-4.38%