Genmab A-S (GMAB) had the highest return in September 2013 by a large-cap US stock, returning 40.5%.

ASSET	MONTH	% RETURN
Genmab A-S (GMAB)	September 2013	40.49%
Grupo Financiero Galicia SA ADR (GGAL)	September 2013	37.03%
Sarepta Therapeutics (SRPT)	September 2013	36.94%
Synnex (SNX)	September 2013	28.58%
Centrais Electricas Brasileiras (EBR)	September 2013	27.72%
Regeneron Pharmaceuticals (REGN)	September 2013	27.19%
Micron Technology (MU)	September 2013	26.77%
Trip Group Ltd ADR (TCOM)	September 2013	24.89%
Axon Enterprise (AXON)	September 2013	24.83%
Ciena (CIEN)	September 2013	23.14%
Alnylam Pharmaceuticals (ALNY)	September 2013	21.37%
Cheniere Energy (LNG)	September 2013	20.68%
ICICI Bank (IBN)	September 2013	20.62%
Facebook (META)	September 2013	20.05%
Nokia (NOK)	September 2013	19.43%
YPF Sociedad Anonima (YPF)	September 2013	19.25%
Ulta Beauty (ULTA)	September 2013	18.72%
Banco Bradesco SA ADR (BBD)	September 2013	18.22%
Banco Santander Brasil SA ADR (BSBR)	September 2013	18.2%
Petróleo Brasileiro SA - Petrobras (PBR.A)	September 2013	17.98%
Sprouts Farmers Market LLC (SFM)	September 2013	17.87%
Delta Air Lines (DAL)	September 2013	17.66%
Centrais Elétricas Brasileiras SA - Eletrobrás (EBR.B)	September 2013	17.63%
Sociedad Quimica y Minera de Chile SA ADR B (SQM)	September 2013	17.55%
Elbit Systems (ESLT)	September 2013	17.23%

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