Mueller Industries (MLI) had the highest return in August 2011 by a large-cap US stock, returning 24.6%.

ASSET	MONTH	% RETURN
Mueller Industries (MLI)	August 2011	24.62%
Agnico Eagle Mines (AEM)	August 2011	23.42%
Logitech International (LOGI)	August 2011	19.73%
Royal Gold (RGLD)	August 2011	19.44%
CF Industries (CF)	August 2011	15.85%
Dollar General (DG)	August 2011	15.42%
Ambev SA ADR (ABEV)	August 2011	12.85%
Zillow (ZG)	August 2011	12.8%
Newmont Goldcorp (NEM)	August 2011	12.59%
Nokia (NOK)	August 2011	11.22%
Wheaton Precious Metals (WPM)	August 2011	10.12%
Alamos Gold (AGI)	August 2011	10.09%
Monster Beverage (MNST)	August 2011	10.05%
O’Reilly Automotive (ORLY)	August 2011	9.82%
Cboe Global Markets (CBOE)	August 2011	9.41%
Celsius (CELH)	August 2011	9.37%
Regeneron Pharmaceuticals (REGN)	August 2011	9.31%
Rollins (ROL)	August 2011	8.7%
Pan American Silver (PAAS)	August 2011	8.32%
Church & Dwight (CHD)	August 2011	7.81%
Gold Fields Ltd ADR (GFI)	August 2011	7.68%
AngloGold Ashanti (AU)	August 2011	7.43%
Dollar Tree (DLTR)	August 2011	7.01%
Axon Enterprise (AXON)	August 2011	6.97%
AutoZone (AZO)	August 2011	6.97%

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