Big Media is getting smaller and more expensive, and that's worrying investors.

Time Warner (TWX) was tumbling Wednesday after the New York-based media company lowered its profit expectations for 2016 to $5.25 a share from an average projection of $5.60, according to a Bloomberg Business survey of Wall Street analysts.

The sharp drop-off in guidance, a common practice during the fourth quarter, was due to increased programming expenses at Time Warner's cable-TV networks, which include TNT and TBS; costs for marketing for its streaming service HBO NOW; and the impact of foreign exchange, which is taking a bite out of non-U.S. profits, said Time Warner CEO Jeff Bewkes said in the company's third-quarter earnings call.

While Bewkes dimmed the company's outlook, the third quarter also produced results that underwhelmed investors.

Revenue at the company's cable-TV networks fell 2% in the third quarter from the same period a year earlier as the number of subscribers declined, triggering lower fees from pay-TV distributors. Additionally, domestic advertising sales at the company's Turner networks were little changed from a year ago, signaling little growth.

Time Warner shares were losing 8.6% to $70.62, extending the company's 2015 decline to 17%.

Similar results could be found at 21st Century Fox (FOXA) - Get Report where revenue at the company's cable networks missed the forecast of analysts while profit for the third quarter also trailed estimates. Ad sales at Fox's flagship broadcasting network fell 5%, a figure that wasn't unexpected. Television revenue was also flat, further evidence that Fox TV, like Turner, is struggling to grow.

Time Warner's admission of a decline in subscribers at its cable network, and therefore lower pay-TV fees, was likely to be felt as well by 21st Century Fox, said Bernstein media analyst Todd Juenger in an investor note. It's not much of a surprise then that Fox stock was plummeting nearly 8% to $28.79, extending its 2015 loss to 27%.

But Fox's biggest drag to earnings came from its film division, where Fantastic Four proved to be a big disappointment at the box office. The superhero movie generated just $56 million domestically and $168 million worldwide, according to Box Office Mojo, a fraction of its cost. Fox's film business generated 28% less revenue in the quarter -- $1.785 billion -- than a year ago.

Media companies continue to be buffeted by concerns that viewers and advertisers are increasingly transitioning to online platforms led by Alphabet's (GOOG) - Get Report (GOOGL) - Get Report YouTube, Netflix (NFLX) - Get Report , Amazon (AMZN) - Get Report Prime and all-purpose social sites such as Facebook (FB) - Get Report and Instagram.

To safeguard its business model, Time Warner is investing in more high-profile content for its subscription-based online offering HBO NOW, which affords viewers access to the premium cable network's extensive library without the need of a pay-TV contract. Time Warner, said Bewkes, also plans to extend the time period that it retains rights to its programming before licensing it to aggregation platforms, a move that may hurt Netflix as well as Amazon.

In recent weeks, Time Warner has inked deals with Vice for a daily news show, Sesame Street for older and new shows, and millennial favorites Jon Stewart and Bill Simmons to do short- and longer-form programming for HBO.

Such programming is certain to attract subscribers to the $15 per month HBO NOW service -- but it also adds to expenses, and a lowering of profit expectations.

CBS (CBS) - Get Report CEO Les Moonves is clearly keenly aware that no one knows how soon the traditional pay-TV bundle of 150-plus channels will unravel. But change is inevitable, as Moonves acknowledged with investors on Tuesday.

"There is no question, there is going to be change from the 180-channel universe," he said in an investor conference call, discussing earnings. "People want more specificity on what they are watching."

To hedge against an acceleration of cord-cutters, or more importantly, cord-nevers -- households that have never had a pay-TV contract -- Moonves is planning to put more exclusive content on its CBS All-Access streaming service. That's similar to the steps HBO CEO Richard Plepler has taken. And CBS said it will produce a new slate of Star Trek episodes for 2017 available only on its online streaming service.

CBS, which continues to win ratings with The Big Bang Theory, Blue Bloods and Scorpion, posted third-quarter profits that beat expectations. Yet in a display of investor uneasiness about the outlook for major media companies, shares of New York-based CBS were slipping 0.8% Wednesday to $47.84.

Discovery Communications (DISCA) - Get Report , which reported its third-quarter earnings on Tuesday, was also falling on Wednesday despite producing results that beat expectations. Silver Spring, Md.-based Discovery posted a third-quarter ad revenue increase of 6% as sales reached $1.56 billion, beating consensus forecasts.

"Third-quarter domestic ad growth was the best it has been in over a year," said John Janedis, the Jefferies media analyst, in an investor note.

Discovery even said it plans to spend roughly $1.5 billion over the next 12 months buying back its stock. But on a day when Time Warner lowered its 2016 forecast, Discovery shares were falling 5.2% to $29.45.