Bloomberg terminals used by subscribers to make trades using real-time developments in business and finance were struck by a "global network problem" Friday, the company's technical department said.

"Our network teams are trying to resolve the problem," a Bloomberg representative said without specifying the cause of the breakdown that led countless screens to go black Friday morning.

Bloomberg terminals feed movements of global equity markets to worldwide subscribers -- many of whom are themselves traders and strategists in the global financial sector, and consider the service an essential tool.

But Friday's global outage even sent terminals within the company offline.

"Even I can't get the terminal to connect," a Bloomberg employee contacted by AFP said, adding the "situation should rapidly get back to normal."

Breakdowns in the Bloomberg system are extremely rare, and finance professionals found themselves stranded when their screens went blank Friday.

"(The outage) is really disruptive for everyone," said London-based Natixis bond strategist Rene Defossez, who is responsible for working daily forecast and advisory models.

"Those function using Bloomberg data, which makes this a real problem."