U.S. mail management company Pitney Bowes Inc has received takeover interest from private equity firms Blackstone Group LP and Carlyle Group LP, according to the Financial Times, citing a Bloomberg report. Pitney's shares closed up nearly 15 percent on Thursday. "We do not comment on rumors or speculation," a Pitney Bowes spokeswoman told Reuters. Blackstone declined to comment, while Carlyle could not be immediately reached for comment. More details awaited.