all 500 stocks in the s and p 500 in the year 2008

Dollar Tree (DLTR) had the best year in 2008 by a US stock in the S&P 500 (GSPC) in 2008, returning 60.9%.

ASSET YEAR % RETURN
Walmart (WMT)
2008
20.31%
Amgen (AMGN)
2008
23.93%
Old Dominion Freight Line (ODFL)
2008
25.38%
Vertex Pharmaceuticals (VRTX)
2008
30.67%
Dollar Tree (DLTR)
2008
60.88%