Inventrust Properties (IVT) had the highest return between 2010 and 2014 by a mid-cap US stock, returning 1,076,380%.

ASSET	YEARS	% RETURN
Inventrust Properties (IVT)	2010-2014	1,076,380%
Vipshop (VIPS)	2010-2014	3,156.64%
ACADIA Pharmaceuticals (ACAD)	2010-2014	2,305.3%
Jazz Pharmaceuticals (JAZZ)	2010-2014	1,931.39%
Patrick Industries (PATK)	2010-2014	1,687.88%
Acadia Healthcare (ACHC)	2010-2014	1,266.29%
Travere Therapeutics (TVTX)	2010-2014	1,260%
Nexstar Broadcasting (NXST)	2010-2014	1,220.98%
Lithia Motors (LAD)	2010-2014	1,014.68%
American Airlines (AAL)	2010-2014	1,013.65%
Bausch Health Companies (BHC)	2010-2014	979.14%
Under Armour Inc A (UAA)	2010-2014	888.71%
Axos Financial (AX)	2010-2014	678.1%
CVR Energy (CVI)	2010-2014	674.61%
Ambarella (AMBA)	2010-2014	655.89%
Polaris Industries (PII)	2010-2014	655.4%
Silicon Motion Technology (SIMO)	2010-2014	645.9%
Melco Resorts & Entertainment (MLCO)	2010-2014	644.82%
Dillard's (DDS)	2010-2014	620.21%
Western Alliance Bancorporation (WAL)	2010-2014	614.66%
Alaska Air (ALK)	2010-2014	597.97%
HCI (HCI)	2010-2014	585.93%
Bath & Body Works (BBWI)	2010-2014	575.55%
Asbury Automotive (ABG)	2010-2014	550%
Dorman Products (DORM)	2010-2014	535.01%

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