Micron Technology (MU) had the lowest return in June 2011 by a US stock in the S&P 500 (GSPC), returning -25.4%.

ASSET	MONTH	% RETURN
Micron Technology (MU)	June 2011	-25.42%
NVIDIA (NVDA)	June 2011	-20.14%
Advanced Micro Devices (AMD)	June 2011	-19.19%
Masco (MAS)	June 2011	-15.46%
Juniper Networks (JNPR)	June 2011	-13.7%
Corpay (CPAY)	June 2011	-11.86%
LyondellBasell Industries (LYB)	June 2011	-11.79%
MGM Resorts International (MGM)	June 2011	-11.7%
Builders FirstSource (BLDR)	June 2011	-11.52%
Regions Financial (RF)	June 2011	-11.41%
Monolithic Power Systems (MPWR)	June 2011	-10.19%
Corning (GLW)	June 2011	-9.93%
Autodesk (ADSK)	June 2011	-9.71%
Mohawk Industries (MHK)	June 2011	-9.61%
Raymond James Financial (RJF)	June 2011	-9.32%
Skyworks Solutions (SWKS)	June 2011	-9.17%
Delta Air Lines (DAL)	June 2011	-9.03%
Adobe Systems (ADBE)	June 2011	-8.92%
Trimble (TRMB)	June 2011	-8.75%
L3Harris Technologies (LHX)	June 2011	-8.6%
Bank of New York Mellon (BK)	June 2011	-8.6%
Avery Dennison (AVY)	June 2011	-8.5%
PulteGroup (PHM)	June 2011	-8.15%
Trane Technologies (TT)	June 2011	-8.14%
Everest (EG)	June 2011	-7.92%