Investors are punishing Ann Arbor-based book store chain Borders Group Inc. for its poor 2009 holiday sales report.

Shares of Borders' stock [NYSE:BGP], which closed at $1.36 on Friday, had dropped 12.5 percent as of 10:16 a.m. to $1.19 since the firm announced disappointing holiday sales results Monday.

Investors appear to be losing faith in Borders after showing some confidence in the stock market rally during the second half of 2009.

Borders' shares averaged about 50 cents during the financial crisis in early 2009 but quickly climbed to a 52-week high of $4.48 in June due to increasing confidence that the company was better positioned in a stabilizing economy.

But Borders shares are back in the basement - which likely reflects concern that the company won't be able to reverse a long-running trend of sliding sales. The firm announced Monday that its total holiday sales had dipped 13.7 percent compared to the same period in 2008.

Borders' market capitalization - the combined value of all of its shares - was about $71 million this morning.

Borders Group Inc. employs more than 800 workers at its Ann Arbor headquarters.

Contact AnnArbor.com’s Nathan Bomey at (734) 623-2587 or nathanbomey@annarbor.com. You can also follow him on Twitter.