American International (AIG) had the highest return in August 2009 by a US stock in the S&P 500 (GSPC), returning 241.1%.

ASSET	MONTH	% RETURN
American International (AIG)	August 2009	241.08%
Citigroup (C)	August 2009	51.98%
United Airlines (UAL)	August 2009	48.33%
Las Vegas Sands (LVS)	August 2009	46.56%
Hartford Financial Services (HIG)	August 2009	39.25%
Insulet (PODD)	August 2009	37.46%
Regions Financial (RF)	August 2009	35.33%
Incyte (INCY)	August 2009	29.98%
Builders FirstSource (BLDR)	August 2009	28.6%
Paramount Global Class B (PARA)	August 2009	27.15%
Lennar (LEN)	August 2009	25.93%
Royal Caribbean Cruises (RCL)	August 2009	24.95%
KKR (KKR)	August 2009	23.39%
Align Technology (ALGN)	August 2009	23.16%
United Rentals (URI)	August 2009	21.24%
DexCom (DXCM)	August 2009	20.34%
Truist Financial (TFC)	August 2009	20.33%
International Paper (IP)	August 2009	19.92%
Jabil Circuit (JBL)	August 2009	19.58%
Capital One Financial (COF)	August 2009	19.36%
Live Nation Entertainment (LYV)	August 2009	19.15%
Broadridge Financial Solutions (BR)	August 2009	19.04%
Nordson (NDSN)	August 2009	18.69%
Interpublic Group of Companies (IPG)	August 2009	18.46%
Garmin (GRMN)	August 2009	18.02%