Enphase Energy (ENPH) had the best month between June 1, 2014 and January 31, 2018 by a US stock in the S&P 500 (GSPC) in December 2015, returning 110.2%.

ASSET	MONTH	% RETURN
Enphase Energy (ENPH)	December 2015	110.18%
Builders FirstSource (BLDR)	April 2015	92.46%
Enphase Energy (ENPH)	November 2017	89.54%
Freeport-McMoran Copper & Gold (FCX)	February 2016	69.55%
Enphase Energy (ENPH)	September 2017	67.03%
Danaher (DHR)	July 2016	64.88%
Paycom Soft (PAYC)	November 2014	61.34%
Enphase Energy (ENPH)	January 2017	46.08%
Targa Resources (TRGP)	April 2016	43.47%
NRG Energy (NRG)	July 2017	42.16%
Builders FirstSource (BLDR)	March 2016	41.41%
Freeport-McMoran Copper & Gold (FCX)	April 2016	41.13%
Caesars Entertainment (CZR)	April 2015	41%
Trimble (TRMB)	October 2015	40.87%
First Solar (FSLR)	February 2015	39.98%
Paycom Soft (PAYC)	August 2014	39.56%
Devon Energy (DVN)	March 2016	38.75%
NVIDIA (NVDA)	May 2017	37.97%
Netflix (NFLX)	January 2018	37.84%
Enphase Energy (ENPH)	August 2014	37.63%
Monster Beverage (MNST)	August 2014	37.6%
Incyte (INCY)	October 2014	36.47%
Enphase Energy (ENPH)	December 2014	36.1%
Freeport-McMoran Copper & Gold (FCX)	December 2017	36.01%
Texas Pacific Land Trust (TPL)	September 2016	35.97%