First Majestic Silver (AG) had the highest return between February 1, 2010 and April 30, 2011 by a mid-cap US stock or mid-cap US stock, returning 572.4%.

ASSET	DATE	% RETURN
First Majestic Silver (AG)	2/1/2010 - 4/30/2011	572.43%
Universal Display (OLED)	2/1/2010 - 4/30/2011	386.62%
IPG Photonics (IPGP)	2/1/2010 - 4/30/2011	381.69%
Novanta (NOVT)	2/1/2010 - 4/30/2011	372.92%
Innospec (IOSP)	2/1/2010 - 4/30/2011	284.68%
Silicon Motion Technology (SIMO)	2/1/2010 - 4/30/2011	283.02%
Bausch Health Companies (BHC)	2/1/2010 - 4/30/2011	281.62%
Jazz Pharmaceuticals (JAZZ)	2/1/2010 - 4/30/2011	238.03%
Golar LNG (GLNG)	2/1/2010 - 4/30/2011	225.03%
Vishay Intertechnology (VSH)	2/1/2010 - 4/30/2011	219.58%
Chart Industries (GTLS)	2/1/2010 - 4/30/2011	198.34%
Melco Resorts & Entertainment (MLCO)	2/1/2010 - 4/30/2011	194.25%
Dillards (DDS)	2/1/2010 - 4/30/2011	190.3%
B2Gold (BTG)	2/1/2010 - 4/30/2011	186.56%
Sapiens International (SPNS)	2/1/2010 - 4/30/2011	180.71%
New Gold (NGD)	2/1/2010 - 4/30/2011	177.53%
CVR Energy (CVI)	2/1/2010 - 4/30/2011	177.17%
WW International, Inc Common Stock (WW)	2/1/2010 - 4/30/2011	174.76%
Crocs (CROX)	2/1/2010 - 4/30/2011	172.49%
Banc of California (BANC)	2/1/2010 - 4/30/2011	172.25%
Quaker Chemical (KWR)	2/1/2010 - 4/30/2011	166.34%
Under Armour Inc A (UAA)	2/1/2010 - 4/30/2011	165.35%
Fortuna Silver Mines (FSM)	2/1/2010 - 4/30/2011	162.85%
Lattice Semiconductor (LSCC)	2/1/2010 - 4/30/2011	162.16%
Viavi Solutions (VIAV)	2/1/2010 - 4/30/2011	159.85%

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