Sarepta Therapeutics (SRPT) had the best month in September 2016 by a large-cap US stock in September 2016, returning 137.2%.

ASSET	MONTH	% RETURN
Sarepta Therapeutics (SRPT)	September 2016	137.2%
Nutanix (NTNX)	September 2016	39.62%
Summit Therapeutics (SMMT)	September 2016	37.33%
Texas Pacific Land Trust (TPL)	September 2016	35.97%
Liberty Media Corporation Series A Liberty Formula One Common Stock (FWONA)	September 2016	34.13%
Liberty Media Corporation Series C Liberty Formula One Common Stock (FWONK)	September 2016	32.61%
Western Digital (WDC)	September 2016	26.36%
Permian Resources (PR)	September 2016	25.6%
MakeMyTrip (MMYT)	September 2016	20.84%
Twilio (TWLO)	September 2016	20.05%
Palo Alto Networks (PANW)	September 2016	19.55%
Western Midstream Partners (WES)	September 2016	17.73%
Seagate Technology (STX)	September 2016	16.2%
BHP (BHP)	September 2016	15.77%
Lithia Motors (LAD)	September 2016	15.74%
Incyte (INCY)	September 2016	15.54%
NXP Semiconductors (NXPI)	September 2016	15.42%
Exelixis (EXEL)	September 2016	14.91%
Pure Storage (PSTG)	September 2016	14.83%
Coherent (COHR)	September 2016	14.55%
ON Semiconductor (ON)	September 2016	14.18%
NetEase (NTES)	September 2016	13.63%
Targa Resources (TRGP)	September 2016	13.37%
Enbridge (ENB)	September 2016	12.72%
Natera (NTRA)	September 2016	12.45%

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