By Ed Frankl

Warren Buffett's Berkshire Hathaway Inc. has tendered its 6.9% stake in Italian insurer Cattolica Assicurazioni SC as part of a takeover bid by Assicurazioni Generali SpA, according to a person familiar with the matter.

The move brings Generali close to having 50% of Cattolica under its control, the person said, although Italy's largest insurer is looking to reach 66.67% ownership as part of its tender offer.

Generali declined to comment. Berkshire Hathaway couldn't immediately be reached for comment.

Trieste-based Generali has launched a 6.75-euro-a-share ($7.85) takeover bid for all shares in its smaller rival, which would value it around EUR1.59 billion.

Milan-listed Cattolica closed at EUR6.97, down 1.1%.

Shares could fall further on Monday as more investors warm to the deal, which Cattolica's board in September called fair value.

Generali controlled 24% of Cattolica ahead of its takeover offer. The remaining shares as part of the bid are valued at about EUR1.18 billion at the price of Generali's offer, with the acceptance period due to close Oct. 29.

The move comes a day after the European Commission authorized the takeover, Generali said late Thursday.

Write to Ed Frankl at edward.frankl@dowjones.com