The Maryland comptroller warned Gov. Martin O’Malley about the risks of taxing Internet sales. Although the state loses millions of dollars in revenue every year from online and catalog sales that are not taxed, changing state laws to allow the taxes would benefit Maryland only slightly, Comptroller Peter Franchot told O’Malley in a letter.

Franchot estimated that the state lost $198 million of sales tax revenue in 2010 due to remote sales — about half of which were by online retailers — representing about 5.4 percent of gross sales tax collection. In fiscal 2013, the state stands to lose $243 million in tax revenue.