U.S. markets opened Thursday's session to the downside even as M A activity appears to be heating up with Comcast's announcement that it will acquire Time Warner Cable in an all-stock deal valued at $45 billion. The deal has been approved by the boards of both companies and is expected to close at the end of 2014. Whole Foods shares are lower at the open after the food purveyor posted fiscal first quarter results which beat forecasts but lowered 2014 guidance. J.C. Penney says its CFO is leaving after just a little more than two years on the job. TheStreet's Jon Marino reports from Wall Street.