Smurfit WestRock (SW) had the highest return in May 2009 by a large-cap US stock, returning 97.1%.

ASSET	MONTH	% RETURN
Smurfit WestRock (SW)	May 2009	97.09%
Fifth Third Bancorp (FITB)	May 2009	70.38%
Jazz Pharmaceuticals (JAZZ)	May 2009	66.67%
Entegris (ENTG)	May 2009	64.57%
Tenet Healthcare (THC)	May 2009	60.62%
Globalstar, Inc Common Stock (GSAT)	May 2009	55%
Chart Industries (GTLS)	May 2009	51.53%
ICICI Bank (IBN)	May 2009	50.94%
Teck Resources Ltd Class B (TECK)	May 2009	48.22%
Live Nation Entertainment (LYV)	May 2009	46.67%
Capital One Financial (COF)	May 2009	46.5%
Cytokinetics (CYTK)	May 2009	46.24%
CME (CME)	May 2009	46.18%
Webster Financial (WBS)	May 2009	45.99%
Pan American Silver (PAAS)	May 2009	42.28%
Prudential Financial (PRU)	May 2009	41.78%
ArcelorMittal SA ADR (MT)	May 2009	40.99%
AES (AES)	May 2009	40.9%
Agnico Eagle Mines (AEM)	May 2009	40.62%
Gildan Activewear (GIL)	May 2009	40.24%
Incyte (INCY)	May 2009	40%
Hartford Financial Services (HIG)	May 2009	39.97%
Principal Financial (PFG)	May 2009	39.45%
TFI International (TFII)	May 2009	38.6%
Huntington Bancshares (HBAN)	May 2009	38.51%

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