Bloomberg, the financial data service used by traders around the world, was hit by an outage on Wednesday, briefly disrupting auctions of bonds in Europe.

The Bloomberg terminal is the crown jewel of the media empire founded by US billionaire Michael Bloomberg in 1981 and counts some 350,000 users worldwide.

The service, which costs subscribers tens of thousands of dollars a year, is ubiquitous in trading rooms, providing live pricing of company stocks, currencies, commodities, bonds and other financial instruments.

Traders and investors also use it for its news content and analytics and to exchange messages with peers around the world.

But several of its functions stopped working or slowed to a crawl on Wednesday.

"Our systems are returning to normal operations and Terminal functionality has been restored following a service disruption earlier today," Bloomberg spokesman Ty Trippet said in a statement.

The company's help desk had told AFP at that a "technical issue" had affected multiple clients and it had deployed technicians to resolve the problem.

The service started working again, but more slowly, at around 1000 GMT.

The problem disrupted bond auctions in Britain, Portugal and Sweden, and by the European Union.

"Due to global technical problems with Bloomberg, the EU postpones the deadline for today's EUB auction by 1 hour... to ensure a smooth functioning of the auction," the European Commission said in a statement.

The UK Debt Management Office said it had to extend the bidding window for a government debt auction due to the "market-wide Bloomberg system issues". The bidding window closed later, at 1030 GMT.

"It's a mess. It's blocking business," Gregoire Kounowski, an investment adviser at London-based wealth manager Norman K., told AFP.

Sweden extended its bidding window by three hours, while Portugal did so for four hours.

Giles Plump, a London-based copper trader at US financial services firm StoneX, told AFP that price feeds were "very intermittent" and some functions were not loading, but those were "not major problems" for him.

A trader in Dubai, who declined to give his name, said the terminal was "down" and "sometimes flickers back to life for five seconds".

Previously, in 2015, Bloomberg terminals went out for two hours, disrupting market action and monitoring around the world.