Moody's Investors Service has downgraded the standalone bank financial strength rating of France’s BNP Paribas, Société Générale and Credit Agricole, primarily due to liquidity and funding constraints.

The move comes shortly after Standard & Poor's warned that big European banks might face ratings downgrades, as Germany’s Commerzbank, Deutsche Bank and BNP Paribas were put on CreditWatch negative.

BNP Paribas and SocGen are both two of the largest wealth management businesses in the eurozone.

The issue of credit rating strength is important for high and ultra HNW clients of such banks who might be concerned about the safety of their own money. In recent years, banks with a AAA or equivalent rating have been keen to stress this point as part of their marketing.

Moody’s has since demoted Société Générale’s rating to C- from C+, reducing its long-term debt and deposit ratings by one level to A1.

“Liquidity and funding conditions have deteriorated significantly for SocGen, which has made extensive use of wholesale funding markets,” the rating agency said in statement.

“While liquid assets have declined only modestly, the probability that the bank will face further funding pressures has risen in line with the worsening European debt crisis,” it said.

Crédit Agricole has been downgraded to C- from C, while BNP Paribas’ rating has fallen two notches to C from B-. Moody’s has cut both banks’ long-term debt and deposit ratings by one notch to Aa3.

Société Générale, BNP Paribas and Crédit Agricole are some of Europe’s largest banks, making them particularly vulnerable to the shortcomings of the euro crisis, the ratings agency said. However, Moody’s believes that the likeliness they will obtain systemic support is “very high”.