Shares of Verizon Communications Inc. fell 0.7% in premarket trade Friday, as investors digested the news that Chief Executive Lowell McAdam was retiring after seven years in charge of the telecommunications giant. Since McAdam became CEO on Aug. 1, 2011, the stock had climbed 36.6% through Thursday, compared with the 17.6% gain in the iShares U.S. Telecommunications ETF and the 14.5% rise in rival AT&T Inc.'s shares over the same time. Meanwhile, the Dow Jones Industrial Average more than doubled during that time, rising 108%. Verizon was added to the Dow in April 2004.