(Reuters) - CBS Corp CBS.N, owner of the most-watched U.S. TV network, on Thursday reported revenue that missed Wall Street estimates largely due to lower ad sales, sending shares down to a 13-month low in extended trading.

FILE PHOTO - The CBS "eye" and logo are seen outside the CBS Broadcast Center on West 57th St. in Manhattan, New York, U.S., April 29, 2016. REUTERS/Brendan McDermid/File Photo

The company’s shares were down 1.6 percent at $53.61 in after-hours trading.

CBS, like its peers, is looking to diversify its revenue away from advertising as more advertisers shift spending to online from television.

The New York-based broadcaster, home to such popular shows as “The Big Bang Theory” and “Homeland,” reported a profit of $1.11 per share, beating analysts’ average estimate of $1.07.

However, Wall Street seized on the company’s revenue results of $3.17 billion, which missed the analysts’ estimate of $3.26 billion, according to Thomson Reuters I/B/E/S.

“CBS makes money through subscriptions and advertising and both of these are at risk,” said Brett Harriss, an analyst at Gabelli & Co, a Rye, New York-based firm that is the second largest shareholder of controlling shares of CBS. “But CBS is the best positioned because they own their own streaming service that can act as a hedge.”

CBS said on Thursday that it receives more revenue per subscriber from digital platforms than traditional ones.

CBS Chief Executive Officer Leslie Moonves told analysts on a call on Thursday that it makes double the amount from an online streaming service subscriber than it does from a traditional cable or satellite subscriber. Furthermore, CBS makes three times as much from a subscriber of its own CBS All Access streaming service.

“Not only are we not as affected as others by cord-cutting, but it has a real measurable upside for us,” Moonves said on the call.

CBS, which owns cable channel Showtime and publishing house Simon & Schuster, said revenue from affiliate and subscription fees -- which includes revenue from cable TV operators and from its own streaming content -- rose 52 percent in the quarter.

CBS is focused on owning more of its own content so that it can make more money from its shows through licensing deals, both domestically and abroad, executives told Reuters.

The company currently owns 65 shows, double what it owned five years ago, executives said.

Despite concerns about National Football League ratings, Moonves said he had not seen one advertiser stop running ads.