The Wall Street Journal will close its Boston bureau to save money, and shift coverage of the mutual fund industry to its money and investing reporting team, the newspaper's editor said on Thursday.

The economic background is painfully obvious to us all, Journal Managing Editor Robert Thomson told the paper's employees in a memo. That there has been truly great reporting... out of Boston over many, many years is not in doubt. But we remain in the midst of a profound downturn in advertising revenue and thus must think the unthinkable.

News Corp, which owns the Journal, will keep sister news organizations Dow Jones Newswires and MarketWatch in Boston, the memo said. An investigative reporting operation for the Journal will remain too, Thomson said.

Nine bureau reporters at the Journal would have to apply for other jobs, the memo said.

A Journal spokesman declined to say how much money the closure will save.

There are no plans to close other U.S. or international bureaus, Thomson wrote. The Journal has 16 U.S. bureaus and 23 outside the United States.

Boston is a financial services hub, home to some of the world's largest mutual fund firms, closely held Fidelity Investments and Sun Life Financial's MFS Investment Management

The closing comes in the same month the Journal reported that it was one of the few U.S. newspapers to report a circulation gain -- of 0.6 percent -- for the six-month period ending in September, compared with last year.

Additionally, the Journal said on Tuesday that it will stop selling its U.S. edition in London, and will offer a redesigned version of its European edition later this year.

Many U.S. newspapers are shedding jobs as advertising revenue falls and circulation declines as more people get their news online for free instead of paying for it in print.

The New York Times Co said earlier this month that it will cut 100 jobs through buyouts, and possibly layoffs, from its namesake newspaper's editorial operations.

The Journal charges for access to its online edition, and News Corp Chief Executive Rupert Murdoch has redoubled his international newspaper empire's efforts to charge for news online. The Journal recently began charging for many of its articles for people who read them on mobile devices.

(Reporting by Robert MacMillan. Additional reporting by Jim Finkle; Editing by Tim Dobbyn)