American Airlines (AAL) had the highest return in July 2008 by a mid-cap US stock, returning 105.7%.

ASSET	MONTH	% RETURN
American Airlines (AAL)	July 2008	105.7%
CSG Systems International (CSGS)	July 2008	62.3%
Cathay General Bancorp (CATY)	July 2008	49.53%
Trex (TREX)	July 2008	49.28%
Atlantic Union Bankshares (AUB)	July 2008	48.57%
Amicus Therapeutics (FOLD)	July 2008	46.23%
JetBlue Airways (JBLU)	July 2008	45.18%
Halozyme Therapeutics (HALO)	July 2008	45.11%
Option Care Health (OPCH)	July 2008	44.87%
Cytokinetics (CYTK)	July 2008	44.26%
VSE (VSEC)	July 2008	44.2%
Dorman Products (DORM)	July 2008	43.8%
Turkcell Iletisim Hizmetleri AS (TKC)	July 2008	42.64%
Bank Ozk (OZK)	July 2008	39.89%
Merit Medical Systems (MMSI)	July 2008	39%
First Bancorp (FBP)	July 2008	37.36%
Glacier Bancorp (GBCI)	July 2008	36.74%
Sanmina (SANM)	July 2008	36.15%
Allegiant Travel (ALGT)	July 2008	35.16%
WesBanco (WSBC)	July 2008	34.3%
Helios Technologies (HLIO)	July 2008	30.17%
MarketAxess (MKTX)	July 2008	29.59%
NetScout Systems (NTCT)	July 2008	29.34%
Ligand Pharmaceuticals (LGND)	July 2008	29.07%
Tetra Tech (TTEK)	July 2008	29.01%

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