Quantum Computing (QUBT) had the highest return between 2008 and 2009 by a US stock with a market cap of $2B+, returning 820%.

ASSET	YEARS	% RETURN
Quantum Computing (QUBT)	2008-2009	820%
Amneal Pharmaceuticals, Inc Class A Common Stock (AMRX)	2008-2009	444.4%
Aura Minerals Inc Common Shares (AUGO)	2008-2009	299.84%
Pegasystems (PEGA)	2008-2009	190.23%
Nova (NVMI)	2008-2009	159.44%
Eldorado Gold (EGO)	2008-2009	137.35%
Trex (TREX)	2008-2009	126.85%
NewMarket (NEU)	2008-2009	115.09%
Sociedad Quimica y Minera de Chile SA ADR B (SQM)	2008-2009	111.01%
Alamos Gold (AGI)	2008-2009	107.45%
Netflix (NFLX)	2008-2009	107.43%
Steven Madden (SHOO)	2008-2009	106.51%
Credit Acceptance (CACC)	2008-2009	100.76%
NetEase (NTES)	2008-2009	97.99%
IAMGold (IAG)	2008-2009	93.6%
Grand Canyon Education (LOPE)	2008-2009	90.1%
Edwards Lifesciences (EW)	2008-2009	89.96%
F5 Networks (FFIV)	2008-2009	89.04%
Booking (BKNG)	2008-2009	87.07%
Dollar Tree (DLTR)	2008-2009	86.34%
ICL Israel Chemicals (ICL)	2008-2009	86.26%
Central Garden & Pet (CENT)	2008-2009	84.48%
Vertex Pharmaceuticals (VRTX)	2008-2009	84.3%
ePlus (PLUS)	2008-2009	82.43%
Northern Oil & Gas (NOG)	2008-2009	82.15%