Macy's (M), the No. 2 U.S. department store chain, is planning a 48-hour holiday shopping marathon, a bold gambit to attract shoppers during the important holiday season when retailers make most of their profits for the year.

The company will keep its 800 stores in 45 states open from 7 a.m. on Dec. 21 through 7 a.m. on Dec. 23. Many Macy's will remain open until midnight on the 23rd and some stores will remain open until 6 p.m. on Christmas Eve.
Obviously, this is good news for shoppers. Whether it will brighten the holidays for the New York chain is another story. Keeping stores open won't be cheap.

Macy's will incur additional costs such as overtime pay for employees and electricity. There may be insurance issues to consider as well.

Moreover, experts argue that gimmicks, such as extending Black Friday, don't generate new sales because they encourage people to make purchases earlier than they would have otherwise. Competition among retailers seems especially intense this year. The National Retail Federation is expecting holiday spending to rise 4.2%, less than last year's 5.6%, but above average nonetheless.

Shares of Macy's are a bargain as well. They are trading at a valuation near a five-year-low. Analysts are predicting that the shares, which have surged more than 20% this year, may hit $45.14 in the next 52 weeks. That's about 16% higher than where it currently trades.

--Jonathan Berr does not own shares of the listed stocks. Follow him on Twitter @jdberr