AngloGold Ashanti (AU) had the highest return in August 2015 by a large-cap US stock, returning 35.3%.

ASSET	MONTH	% RETURN
AngloGold Ashanti (AU)	August 2015	35.33%
Alamos Gold (AGI)	August 2015	27.73%
Gold Fields Ltd ADR (GFI)	August 2015	25.2%
Paycom Soft (PAYC)	August 2015	20.4%
Sociedad Quimica y Minera de Chile SA ADR B (SQM)	August 2015	16.15%
Best Buy (BBY)	August 2015	14.06%
Pan American Silver (PAAS)	August 2015	12.72%
Topbuild (BLD)	August 2015	12.44%
NVIDIA (NVDA)	August 2015	12.27%
Agnico Eagle Mines (AEM)	August 2015	11.86%
Incyte (INCY)	August 2015	11.42%
Huazhu (HTHT)	August 2015	11.18%
DexCom (DXCM)	August 2015	10.75%
Sysco (SYY)	August 2015	10.69%
Emera (EMA)	August 2015	9.4%
Ubiquiti Networks (UI)	August 2015	9.4%
BWX Technologies (BWXT)	August 2015	8.62%
Motorola Solutions (MSI)	August 2015	7.89%
Franco-Nevada (FNV)	August 2015	7.73%
Grupo Aeroportuario del Pacifico SAB De CV ADR (PAC)	August 2015	7.63%
Martin Marietta Materials (MLM)	August 2015	7.39%
Fabrinet (FN)	August 2015	7.11%
TechnipFMC (FTI)	August 2015	7.05%
First Solar (FSLR)	August 2015	7.02%
Constellation Brands Inc Class A (STZ)	August 2015	6.39%

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