UPDATE 2-Swiss stocks - Factors to watch on July 7

ZURICH, July 7 (Reuters) - Swiss shares were expected to open firmer on Tuesday, helped by a rally of defensive U.S. stocks on Monday although caution remained ahead of the second-quarter earnings season.

The blue chip SMI index .SSMI was seen opening up 31 points at 5,385 points, according to pre-market data from bank Clariden Leu CLPRE.

The following are some of the main factors expected to affect Swiss stocks on Tuesday:

UBS (UBSN.VX) (UBS.N)

U.S. tax authorities have discovered far fewer than the 52,000 accounts with Swiss bank UBS AG suspected of being used by Americans to avoid taxes, the U.S. government said in a court filing on Monday.

For related news click on [UBSN.VX]

CLARIANT (CLN.VX)

Swiss speciality chemicals company Clariant AG (CLN.VX) has agreed an amendment on its 750 million Swiss francs ($690 million) syndicated loan.

For related news click on [CLN.VX]

SANTHERA (SANN.S)

Swiss specialty pharmaceutical company Santhera Pharmaceuticals said it was cutting jobs and stopping in-house drug discovery to preserve cash as it seeks further approvals for its lead drug.

For related news click on [SANN.S]