GENEVA (Reuters) - Swiss bank UBS (>> UBS Group AG) will report a year-on-year increase of about 25 percent in quarterly net profit on Tuesday, with around 1.5 billion francs of earnings in the second quarter, newspaper SonntagsZeitung said on Sunday, citing an anonymous source.

UBS spokesman Mark Hengel declined to comment on the report.

The newspaper said the quarterly earnings, which would be much higher than most analysts' estimates, would bring net profit for the first half of 2015 to about 3.5 billion Swiss francs ($3.64 billion), a 50 percent increase from the first half of 2014.

The report cited an insider as saying the quarterly profit would have been even higher, if not for write-offs of about 200 million francs.

More than half of the quarterly net profit was generated by the bank's Swiss subsidiary, with 700 million francs from corporate banking and 150 million in asset management, the newspaper said.

UBS's chief rival, Credit Suisse (>> Credit Suisse Group AG), reported 1.1 billion francs of quarterly net profit last week, outstripping the average expectation of 783 million francs.

(Reporting by Tom Miles, additional reporting by Oliver Hirt, editing by David Evans)

Stocks treated in this article : Credit Suisse Group AG, UBS AG, UBS Group AG