The Japanese electronic giant, Sony, has had its credit rating cut to junk status by ratings agency Moody's.
Ambac, which has already seen its crucial AAA financial strength rating cut to AA by Fitch Ratings, gained $1.94, or 16.7%, to $13.58 Friday, while MBIA added 40 cents, or 2.6%, to $15.90.
Ambac has already seen its rating cut to AA by Fitch Ratings (See: "Ambac Gets Downgraded"), and both major insurers are in at least some danger of downgrades at the other major ratings agencies, Moody's Investor Services and Standard & Poor's.
This week the Netherlands had the outlook on its AAA rating cut from stable to negative by Fitch, a ratings agency, on the basis of falling house prices and concerns about the banking system.
Fitch Ratings' downgrade in November was Toyota's first credit rating cut in a decade.
Notwithstanding the rating cut, Treasuries are still deemed safe.
The rating cut "reinforces the perilous economic position the U.K. is in," Kathleen Brooks, research director at Forex.com, said.
The rating cut was widely expected but still offered ammunition to those critical of Prime Minister David Cameron's austerity plan.
Outside in the real world, Spain has just had its credit rating cut from A to BBB+.
Moody's more sober view, and any future rating cut, would increase the cost of future borrowings for the stadium.
Ambac has had its credit rating cut by Fitch and is on negative watch by Moody's and Standard & Poor's.
