By Andrew Hurst, European Banking Correspondent

ZURICH (Reuters) - Credit Suisse (CSGN.VX: Quote, Profile, Research) may face losses on a money market fund that went sour but is unlikely to make big fourth-quarter writedowns on its commercial mortgage and leveraged-finance business, analysts said on Monday.

Swiss newspaper Sonntag said on Sunday CS would have to write down 2.5 billion Swiss francs ($2.24 billion) on leveraged loans and commercial mortgage business in the fourth quarter. Analysts said they were skeptical of the report.

Shares in CS dropped as much as 3.2 percent and were trading 2.1 percent lower at 64.30 francs by 1345 GMT.

Concerns that the bank's exposure to commercial mortgages could come back to haunt it have weighed on the bank's stock for months. Its shares fell 19.7 percent last year.

"It is hard to square (reconcile) a 2.5 billion Swiss franc writedown figure with results from the U.S. investment banks in the fourth quarter, where you saw some gains on leveraged loans previously written down in the third quarter," said Matthew Clark, an analyst at Keefe, Bruyette and Woods (KBW).

CS, which reports fourth-quarter results on Feb. 12, has so far emerged relatively unscathed from the U.S. subprime mortgage crisis which forced many banks, including its local Swiss rival UBS (UBSN.VX: Quote, Profile, Research), to make huge writedowns.

But losses at a money market fund which invested some of its funds in asset-backed securities, whose value was wiped out by the subprime crisis, may force CS to take more charges in the final quarter.

"The writedowns I can see are on money market funds," said Dirk Becker at Landesbanki Kepler in Frankfurt. "They (Sonntag) talk of the bank taking 6.5 billion francs onto their balance sheet and writing off 1.3 billion francs. This sounds plausible," said Becker.