Media executives have been making the case recently that ad markets are starting to recover, and now some evidence has emerged to support it.

In recent days, large advertisers have unveiled new marketing campaigns and reported increased spending on advertising. Such news is pleasing to media companies as ad spending dropped sharply last year amid the global financial crisis only to muddle along in its aftermath as consumers reined in their spending habits and U.S. automakers General Motors Corp. and Chrysler Group LLC descended into bankruptcy.

However, it remains unclear if the positive signs are sustainable or if they can bring an end the recent string of advertising declines. Jon Swallen, senior vice president of research with ad tracking firm TNS Media, said July and August showed some moderation of the pace of decline for ad spending, but that was largely due to easing comparisons.

"Even if the minus signs are getting smaller, continued minus signs are a bad sign, because we're coming up against the really sharp declines that occurred last year," Swallen said. "There are no real signs of improvement yet in my data."

According to TNS, advertising declines have held steady at between 13% and 15% through the first half of the year.

Nonetheless, at a media conference last week hosted by Goldman Sachs, a parade of media executives made their most optimistic comments this year about advertising.

News Corp. (NWS, NWSA) Chief Executive Rupert Murdoch told analysts that ad markets remain below 2007 levels but are "much better than they were four months ago," adding that results are "getting better every month and getting better every week." CBS Corp. (CBS) Chief Executive Les Moonves echoed those sentiments, noting that the company has sold 70% of its ad inventory for February's Super Bowl XLIV.

And recent anecdotal evidence supports their comments.

For example, General Mills Inc. (GIS) - a force in advertising markets - reported Wednesday that it ratcheted up its media and advertising spending by 16% in its fiscal first quarter ended Aug. 30. That news came after the company's counterpart, ConAgra Foods Inc. (CAG), said it would spend "slightly more" on advertising and promotions.

Elsewhere, the world's largest automaker, Toyota Motor Corp. (TM), said last week that it is planning a $1 billion marketing campaign aimed at reviving its U.S. sales. General Motors, meanwhile, has launched an ad campaign of its own titled "May The Best Car Win," aimed at reversing perceptions that its product quality lags its competitors.

The news could ease concerns about the bet made by most major TV networks over the summer to hang onto a larger portion of ad inventory for the new programming season in hopes that a resurgent economy would lead to more pricing power.

Ad buyers, though, remain hesitant.

"All I see are signs that things aren't getting any worse," said Gary Carr, director of national broadcast at media agency TargetCast tcm. "Maybe things are getting a little better, but nothing is going to really change until we see jobs being created and consumers are able to start spending money again. I'm not seeing any rush back into the market now."

Gould said that while he expects earnings for media companies to rise each year, many of his 2011 estimates remain below 2008 results. He expects media conglomerates with a concentration of cable networks, like Time Warner Inc. (TWX), Viacom Inc. (VIA) and Discovery Communications Inc. (DISCA), to surpass their 2008 earnings in 2011, while those with more broadcasting properties, like Walt Disney Co. (DIS) and CBS will lag.

Gould expects News Corp., which owns this newswire and The Wall Street Journal, to barely beat its 2008 results in 2011.

Plus, when the advertising market does rebound, the spending is unlikely to match past patterns because advertisers are experimenting with new media alternatives.

"The old days of carpet bombing the U.S. with network TV ads and expecting to reach everybody are over," said John McDonald, a spokesman for GM. "We continue to shift our marketing and ad resources to where people are and that means it's coming out of major broadcast TV and radio spots and into more online, social media areas where consumers are willing to spend time and interact with brands."

-By Nat Worden, Dow Jones Newswires; (212) 416-2472; nat.worden@dowjones.com