Sandstorm Gold Ltd N (SAND) had the highest return between 2010 and 2012 by a mid-cap US stock, returning 1,260,911.1%.

ASSET	YEARS	% RETURN
Sandstorm Gold Ltd N (SAND)	2010-2012	1,260,911.11%
Aris Mining (ARMN)	2010-2012	29,795.16%
CVR Energy (CVI)	2010-2012	587.17%
Jazz Pharmaceuticals (JAZZ)	2010-2012	560.67%
Patrick Industries (PATK)	2010-2012	532.55%
Acadia Healthcare (ACHC)	2010-2012	421.21%
First Majestic Silver (AG)	2010-2012	394.85%
Melco Resorts & Entertainment (MLCO)	2010-2012	385.3%
Sirius XM (SIRI)	2010-2012	381.69%
Dillard's (DDS)	2010-2012	379.63%
Lithia Motors (LAD)	2010-2012	374.18%
Dorman Products (DORM)	2010-2012	364.91%
Bausch Health Companies (BHC)	2010-2012	350.7%
Mesoblast (MESO)	2010-2012	342.88%
Cirrus Logic (CRUS)	2010-2012	320.46%
HF Sinclair (DINO)	2010-2012	314.08%
Silicon Motion Technology (SIMO)	2010-2012	313.37%
Polaris Industries (PII)	2010-2012	307.81%
IPG Photonics (IPGP)	2010-2012	298.66%
Chart Industries (GTLS)	2010-2012	296.72%
PriceSmart (PSMT)	2010-2012	292.76%
Delek US Energy (DK)	2010-2012	285.84%
Golar LNG (GLNG)	2010-2012	275.54%
Travere Therapeutics (TVTX)	2010-2012	272.22%
Under Armour Inc A (UAA)	2010-2012	253.33%

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