Flutter Entertainment (FLUT) had the highest return in June 2009 by a large-cap US stock, returning 79.8%.

ASSET	MONTH	% RETURN
Flutter Entertainment (FLUT)	June 2009	79.78%
KKR (KKR)	June 2009	49.85%
United Rentals (URI)	June 2009	34.65%
Penske Automotive (PAG)	June 2009	30.2%
Ulta Beauty (ULTA)	June 2009	28.56%
Dr Reddy’s Laboratories Ltd ADR (RDY)	June 2009	27.16%
Grupo Aeroportuario del Pacifico SAB De CV ADR (PAC)	June 2009	25.17%
CBRE Group Inc Class A (CBRE)	June 2009	23.65%
Magna International (MGA)	June 2009	23.62%
MercadoLibre (MELI)	June 2009	22.85%
ICON (ICLR)	June 2009	21.68%
Deckers Outdoor (DECK)	June 2009	20.82%
Kratos Defense & Security Solutions (KTOS)	June 2009	20.27%
Encompass Health (EHC)	June 2009	20.23%
Vertex Pharmaceuticals (VRTX)	June 2009	19.9%
J M Smucker (SJM)	June 2009	19.62%
Waste Connections (WCN)	June 2009	18.13%
Regeneron Pharmaceuticals (REGN)	June 2009	17.89%
Waters (WAT)	June 2009	17.65%
Seagate Technology (STX)	June 2009	16.29%
Super Micro Computer (SMCI)	June 2009	15.89%
Somnigroup International (SGI)	June 2009	15.87%
Bank of America (BAC)	June 2009	15.79%
SEI Investments (SEIC)	June 2009	15.49%
NRG Energy (NRG)	June 2009	15.12%

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