Even Warren Buffett can’t escape the sting of the declining newspaper business.

The billionaire’s papers saw a collective 5.6 percent drop in daily readers, according to the latest annual report of his investment firm, Berkshire Hathaway Inc. Readership fell at 26 of the 28 newspapers he’s owned for more than a year, according to a comparison of a chart in the March 1 document and the prior annual report.

Buffett has acquired smaller dailies such as Alabama’s Dothan Eagle and Nebraska’s Kearney Hub with the idea that they would be crucial sources of local information with few competitors. Yet national publications such as the New York Times have moved more quickly to adopt digital subscriptions, expanding circulation to help make up for the still-declining advertising business.

While his newspapers are embarking on their own digital strategy, Buffett hasn’t been able to move speedily enough to avoid the erosion that has afflicted the industry. U.S. newspaper revenue has fallen by more than a third since it hit its sales peak of $60.2 billion in 2005, according to the Newspaper Association of America.

The slide in Buffett’s newspapers represents the first full yearly comparison of his newspaper empire, which has been expanding since late 2011 with the $200 million purchase of his hometown daily, the Omaha World-Herald. In total, Buffett has spent at least $344 million purchasing news properties across the U.S., betting that despite the industry’s downturn, local news will win out in the end.

‘Tightly Bound’

“Papers delivering comprehensive and reliable information to tightly bound communities and having a sensible Internet strategy will remain viable for a long time,” he wrote in an investor letter included in the 2012 annual report. “We do not believe that success will come from cutting either the news content or frequency of publication.”

Buffett’s letter in this year’s report didn’t mention his newspapers.

The New York Times, which began charging readers for online access in 2011, reported a 15 percent increase in daily circulation, including print and digital readers, in 2013 from the year before. Daily circulation at Gannett Co.’s USA Today surged 65 percent, though that included access through the company’s free mobile applications.

On the other hand, Buffett’s small-town papers did better than many large regional publications. Daily circulation at Gannett’s Arizona Republic and Tennessean each slid 11 percent last year.