Norway's sovereign wealth fund, the largest in the world, lost money in the third quarter, its manager said Thursday.

The fund returned minus 0.5% from July through September, Norges Bank Investment Management said in a release. The loss came to 278 billion kroner, it said. CNBC and Reuters put that at about $29.7 billion. CNBC and Reuters said the fund is worth about $2.3 trillion.

Rising interest rates hurt the fund's bonds, the manager said. Its bond holdings lost 3.5%, and its stocks returned 0.5%, CNBC reported. The fund did 0.18 percentage points worse than its benchmark, the release said.

"The fund's return was close to flat, ending slightly negative as rising interest rates led to weaker results on our fixed-income investments," said Deputy CEO Trond Grande, according to the release. He said energy companies rose the most, while utilities and real estate fell.

The fund's value fell by 670 billion kroner in the quarter, the manager said. A stronger krone cut the value by 472 billion kroner. The fund also took in 80 billion kroner after costs. It was worth 22,014 billion kroner on September 30, the release said.

About 72% of the fund is in stocks, the release said. The fund owns about 1.5% of all listed companies in the world, CNBC and Reuters reported. CNBC said that makes it the world's largest single investor.

The third quarter saw a global bond market rout, CNBC reported. Government bond yields rose as central banks raised rates and worries about inflation and debt grew, CNBC said.

Grande said the fund had been "a little bit cautious" on stocks and on some big tech companies, Reuters reported. He called these "just smaller underweights." He said the fund had no plans for now to change that, according to Reuters.

The fund invests money Norway earns from oil and gas, Reuters reported.

What we know: The fund lost 278 billion kroner in the third quarter as bonds fell.
What we don't: How the fund will fare in the fourth quarter.