Bank of America (BAC) had the lowest return in April 2014 by a mega-cap US stock, returning -12.4%.

ASSET	MONTH	% RETURN
Bank of America (BAC)	April 2014	-12.38%
ASML Holding NV ADR (ASML)	April 2014	-12.06%
Salesforce (CRM)	April 2014	-10.35%
Amazon (AMZN)	April 2014	-10.04%
Palo Alto Networks (PANW)	April 2014	-9.82%
Amgen (AMGN)	April 2014	-9.64%
UnitedHealth (UNH)	April 2014	-8.88%
Netflix (NFLX)	April 2014	-8.45%
KLA (KLAC)	April 2014	-8.01%
JPMorgan Chase (JPM)	April 2014	-7.58%
Visa Inc Class A (V)	April 2014	-6.67%
Applied Materials (AMAT)	April 2014	-6.43%
Thermo Fisher Scientific (TMO)	April 2014	-5.43%
Alphabet Inc Class A (GOOGL)	April 2014	-4.6%
Toyota Motor Corporation ADR (TM)	April 2014	-4.01%
Texas Instruments (TXN)	April 2014	-3.33%
American Express (AXP)	April 2014	-3.04%
Goldman Sachs (GS)	April 2014	-3%
Mitsubishi UFJ Financial Group Inc ADR (MUFG)	April 2014	-2.9%
Marvell Technology (MRVL)	April 2014	-2.76%
Mastercard (MA)	April 2014	-2.11%
Microsoft (MSFT)	April 2014	-1.82%
Broadcom (AVGO)	April 2014	-1.63%
LIN TV (LIN)	April 2014	-1.52%
Facebook (META)	April 2014	-1.12%

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