ACADIA Pharmaceuticals (ACAD) had the highest return between 2010 and 2015 by a mid-cap US stock, returning 2,600.8%.

ASSET	YEARS	% RETURN
ACADIA Pharmaceuticals (ACAD)	2010-2015	2,600.76%
Vipshop (VIPS)	2010-2015	2,444.97%
Cidara Therapeutics (CDTX)	2010-2015	2,045%
Travere Therapeutics (TVTX)	2010-2015	2,043.33%
Patrick Industries (PATK)	2010-2015	1,668.25%
Nexstar Broadcasting (NXST)	2010-2015	1,418.34%
Lithia Motors (LAD)	2010-2015	1,281.39%
CleanSpark (CLSK)	2010-2015	1,053.86%
Silicon Motion Technology (SIMO)	2010-2015	909.66%
Alaska Air (ALK)	2010-2015	850.99%
Western Alliance Bancorporation (WAL)	2010-2015	821.87%
Ligand Pharmaceuticals (LGND)	2010-2015	799.65%
MarketAxess (MKTX)	2010-2015	788.99%
Caesars Entertainment (CZR)	2010-2015	746.15%
Axos Financial (AX)	2010-2015	742%
Alkermes (ALKS)	2010-2015	738.23%
Ambarella (AMBA)	2010-2015	730.7%
CVR Energy (CVI)	2010-2015	726.41%
Bath & Body Works (BBWI)	2010-2015	682.12%
Bausch Health Companies (BHC)	2010-2015	666.5%
Bank Ozk (OZK)	2010-2015	633.55%
Sapiens International (SPNS)	2010-2015	622.97%
Sirius XM (SIRI)	2010-2015	579.48%
Repligen (RGEN)	2010-2015	578.42%
Middleby (MIDD)	2010-2015	554.95%

Mid-cap stocks are treated as having a market cap between $2B and $10B.