Speculation builds on a Verizon-Charter tie-up, no offer made

U.S. cable company Charter Communication Inc shares rose as much as 10 percent on Thursday after the Wall Street Journal reported a preliminary approach by Verizon Communications Inc about a tie-up, but Reuters sources said no proposal was made. Speculation over a combination of the two companies has been building steadily since last month, when Verizon Chief Executive Officer Lowell McAdam told Wall Street analysts that such a deal would make "industrial sense." Analysts and investors have pred