Petroleo Brasileiro Petrobras SA ADR (PBR) had the highest return in April 2015 by a US stock with a market cap of $80B+, returning 52.5%.

ASSET	MONTH	% RETURN
Petroleo Brasileiro Petrobras SA ADR (PBR)	April 2015	52.49%
Petróleo Brasileiro SA - Petrobras (PBR.A)	April 2015	37.13%
Netflix (NFLX)	April 2015	33.29%
NetEase (NTES)	April 2015	22.4%
Newmont Goldcorp (NEM)	April 2015	21.35%
Microsoft (MSFT)	April 2015	19.8%
Tesla (TSLA)	April 2015	19.79%
MercadoLibre (MELI)	April 2015	15.81%
HSBC Holdings PLC ADR (HSBC)	April 2015	15.71%
Amazon (AMZN)	April 2015	13.35%
Sumitomo Mitsui Financial (SMFG)	April 2015	13.13%
Mitsubishi UFJ Financial Group Inc ADR (MUFG)	April 2015	12.52%
Southern Copper (SCCO)	April 2015	11.58%
BHP (BHP)	April 2015	11.52%
AbbVie (ABBV)	April 2015	11.48%
Royal Bank of Canada (RY)	April 2015	10.99%
Philip Morris International (PM)	April 2015	10.89%
Bank of Nova Scotia (BNS)	April 2015	10.81%
Sony (SONY)	April 2015	10.09%
Bank of Montreal (BMO)	April 2015	9.91%
BP PLC ADR (BP)	April 2015	9.6%
GE Aerospace (GE)	April 2015	9.55%
Salesforce (CRM)	April 2015	9.49%
Caterpillar (CAT)	April 2015	9.46%
Rio Tinto ADR (RIO)	April 2015	9.16%