Updated with statement from Standard & Poor's

NEW YORK ( TheStreet) - Standard and Poor's said after the close on Monday that it is placing 15 nations in the euro zone under review for possible downgrade.

The review could lead to a possible downgrade of triple-A rated sovereigns Austria, Belgium, Finland, Germany, Netherlands, and Luxembourg by a notch. France, Italy and other nations in the region could lose up to two notches in their rating.

"Today's CreditWatch placements are prompted by our belief that systemic stresses in the eurozone have risen in recent weeks to the extent that they now put downward pressure on the credit standing of the eurozone as a whole," S&P said in a statement.

A "creditwatch negative," means there is a one-in two chance of a downgrade within 90 days.

Tightening credit conditions, markedly higher risk premiums on the growing number of sovereigns, including Triple-A rated countries, continuing disagreements between policy makers on how to tackle market confidence, the high levels of government and household indebtedness across a large area of the Eurozone, and the rising risk of an economic recession in Europe in 2012 were some of the factors that had led to increased stresses, the firm said.

The firm is expected to conclude its review as soon as possible following the scheduled EU summit on Dec. 8 and Dec. 9.

Reports of S&P's rating action had already leaked earlier in the day, with Financial Times reporting that triple A rated sovereigns would be placed under creditwatch negative. Bloomberg later reported all 17 nations will be placed under review.

S&P said on Monday that it maintained the negative outlook for Cyprus and did not place Greece under review as its rating of "CC" already implied a high probability of default.

Stocks finished higher on Monday, with a particularly strong performance from bank stocks, despite rumors of the S&P action.

--Written by Shanthi Bharatwaj in New York

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