Wells Fargo (WFC) had the highest return in April 2009 by a mega-cap US stock, returning 45.8%.

ASSET	MONTH	% RETURN
Wells Fargo (WFC)	April 2009	45.85%
Bank of America (BAC)	April 2009	38.45%
Salesforce (CRM)	April 2009	36.95%
JPMorgan Chase (JPM)	April 2009	30.72%
GE Aerospace (GE)	April 2009	27.65%
ASML Holding NV ADR (ASML)	April 2009	23.18%
HSBC Holdings PLC ADR (HSBC)	April 2009	21.17%
Apple (AAPL)	April 2009	20.88%
Toyota Motor Corporation ADR (TM)	April 2009	19.63%
Visa Inc Class A (V)	April 2009	18.65%
Taiwan Semiconductor Manufacturing (TSM)	April 2009	18.5%
NVIDIA (NVDA)	April 2009	17.87%
Cisco Systems (CSCO)	April 2009	17.02%
Alphabet Inc Class A (GOOGL)	April 2009	15.18%
UnitedHealth (UNH)	April 2009	14.12%
Home Depot (HD)	April 2009	13.69%
LIN TV (LIN)	April 2009	12.75%
Mastercard (MA)	April 2009	12.38%
Microsoft (MSFT)	April 2009	11.14%
Berkshire Hathaway (BRK.B)	April 2009	10.85%
Amazon (AMZN)	April 2009	10.28%
Berkshire Hathaway (BRK.A)	April 2009	9.56%
SAP SE ADR (SAP)	April 2009	9.3%
Oracle (ORCL)	April 2009	8.57%
International Business Machines (IBM)	April 2009	7.36%

Mega-cap stocks are treated as having a market cap of $200B+.