Neurocrine Biosciences (NBIX) had the highest return between 2014 and 2015 by a large-cap US stock, returning 510.2%.

ASSET	YEARS	% RETURN
Neurocrine Biosciences (NBIX)	2014-2015	510.25%
Genmab A-S (GMAB)	2014-2015	234.05%
Palo Alto Networks (PANW)	2014-2015	210.6%
Broadcom (AVGO)	2014-2015	182.33%
Skyworks Solutions (SWKS)	2014-2015	175.89%
Coca-Cola Consolidated (COKE)	2014-2015	155.5%
NetEase (NTES)	2014-2015	141.72%
Tower Semiconductor (TSEM)	2014-2015	141.17%
Edwards Lifesciences (EW)	2014-2015	140.5%
MACOM Technology Solutions (MTSI)	2014-2015	137.04%
DexCom (DXCM)	2014-2015	132.34%
Southwest Airlines (LUV)	2014-2015	131.7%
Manhattan Associates (MANH)	2014-2015	126.01%
Centene (CNC)	2014-2015	123.24%
Royal Caribbean Cruises (RCL)	2014-2015	121.88%
Monster Beverage (MNST)	2014-2015	119.44%
Kroger (KR)	2014-2015	118.55%
Netflix (NFLX)	2014-2015	118.28%
Incyte (INCY)	2014-2015	115.52%
IES (IESC)	2014-2015	114.53%
NVIDIA (NVDA)	2014-2015	114.24%
Paycom Software (PAYC)	2014-2015	110.22%
Repligen (RGEN)	2014-2015	105.9%
Constellation Brands Inc Class A (STZ)	2014-2015	104.96%
Flutter Entertainment (FLUT)	2014-2015	103.47%

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