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	25.19%
Amkor Technology (AMKR)	August 2015	22.17%
Paycom Software (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%
IAMGold (IAG)	August 2015	12.84%
Pan American Silver (PAAS)	August 2015	12.72%
NVIDIA (NVDA)	August 2015	12.26%
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%
Applied Industrial Technologies (AIT)	August 2015	10.38%
Emera (EMA)	August 2015	9.4%
Ubiquiti Networks (UI)	August 2015	9.4%
BWX Technologies (BWXT)	August 2015	8.62%
Equinox Gold (EQX)	August 2015	8.47%
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%

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