Builders FirstSource (BLDR) had the highest return in April 2015 by a large-cap US stock, returning 92.5%.

ASSET	MONTH	% RETURN
Builders FirstSource (BLDR)	April 2015	92.46%
Petroleo Brasileiro Petrobras SA ADR (PBR)	April 2015	52.49%
Vale SA ADR (VALE)	April 2015	41.88%
Petróleo Brasileiro SA - Petrobras (PBR.A)	April 2015	37.12%
Netflix (NFLX)	April 2015	33.29%
Centrais Electricas Brasileiras (EBR)	April 2015	27.6%
Axon Enterprise (AXON)	April 2015	25.74%
Antero Resources (AR)	April 2015	25.2%
Cameco (CCJ)	April 2015	24.86%
NetEase (NTES)	April 2015	22.4%
Freeport-McMoran Copper & Gold (FCX)	April 2015	22.17%
Newmont Goldcorp (NEM)	April 2015	21.35%
AngloGold Ashanti (AU)	April 2015	20.02%
Microsoft (MSFT)	April 2015	19.8%
Tesla (TSLA)	April 2015	19.79%
Equinor ASA ADR (EQNR)	April 2015	19.2%
TechnipFMC (FTI)	April 2015	18.58%
Banco Santander Brasil SA ADR (BSBR)	April 2015	17.75%
Barrick Gold (GOLD)	April 2015	17.62%
Juniper Networks (JNPR)	April 2015	17.47%
Alamos Gold (AGI)	April 2015	17.29%
LyondellBasell Industries (LYB)	April 2015	17.2%
MercadoLibre (MELI)	April 2015	15.81%
HSBC Holdings PLC ADR (HSBC)	April 2015	15.71%
Bancolombia SA ADR (CIB)	April 2015	15.04%

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