Sandstorm Gold Ltd N (SAND) had the highest return between 2009 and 2010 by a mid-cap US stock, returning 649,100%.

ASSET	YEARS	% RETURN
Sandstorm Gold Ltd N (SAND)	2009-2010	649,100%
Aris Mining (ARMN)	2009-2010	236,485.18%
Dana (DAN)	2009-2010	2,194.65%
Avis Budget (CAR)	2009-2010	2,091.48%
Uranium Energy (UEC)	2009-2010	1,625.71%
Nova (NVMI)	2009-2010	1,410.91%
Crocs (CROX)	2009-2010	1,280.65%
Sirius XM (SIRI)	2009-2010	1,258.29%
Onto Innovation (ONTO)	2009-2010	1,015.65%
Pilgrims Pride (PPC)	2009-2010	958.25%
Jazz Pharmaceuticals (JAZZ)	2009-2010	952.41%
Northern Oil & Gas (NOG)	2009-2010	942.53%
Tower Semiconductor (TSEM)	2009-2010	907.21%
Dillard's (DDS)	2009-2010	885.75%
Qorvo (QRVO)	2009-2010	830.38%
NovaGold Resources (NG)	2009-2010	814.77%
Nexstar Broadcasting (NXST)	2009-2010	794.04%
Camtek (CAMT)	2009-2010	760.98%
Amneal Pharmaceuticals, Inc Class A Common Stock (AMRX)	2009-2010	704.4%
First Majestic Silver (AG)	2009-2010	702.2%
Fortuna Silver Mines (FSM)	2009-2010	682.04%
B2Gold (BTG)	2009-2010	649.95%
New Gold (NGD)	2009-2010	645.04%
Globalstar, Inc Common Stock (GSAT)	2009-2010	625%
Grupo Financiero Galicia SA ADR (GGAL)	2009-2010	612.09%

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