Complex sentence: The market continued to decline between late 2008 and early 2009 surrounding the events involving the financial crisis of 2008, reaching a nearly 13-year closing low at 676.53 on March 9,2009.
Split into simpler sentences: The market continued to decline through 2009, surrounding the financial crisis of 2008. The index reached a nearly 13-year low, closing at 676.53 on March 9,2009.