Germany, the Netherlands and Luxembourg had the outlooks for their Aaa credit ratings lowered to negative Monday by Moody's Investors Service, which cited “rising uncertainty about Europe’s debt crisis.

Risks that Greece may leave the 17-nation euro currency and “increasing likelihood” of collective support for European countries such as Spain and Italy were among reasons for the change, Moody’s said yesterday in a statement reported by Bloomberg.

“Given the greater ability to absorb the costs associated with this support, this burden will likely fall most heavily on more highly rated member states if the euro area is to be preserved in its current form,” Moody’s said.

With “Germany’s central position in the euro zone, the idea that it could be somehow isolated from the general deterioration of the euro area is not realistic,” said Nicolas Veron, senior fellow at Bruegel, a Brussels-based research organization. “From this standpoint, the downgrade sounds logical.”

Yields on German 10-year bonds were 1.18 percent Monday, down from 1.83 percent at the end of last year. The Netherland’s securities of the same maturity yield 1.63 percent, while those of Luxembourg yield 1.71 percent.