ROME, Oct 28 (Reuters) - Italy's top insurer Generali secured a majority stake in Cattolica on Thursday through its 1.17 billion euro buyout offer for the smaller rival, aimed at further strengthening its domestic leadership.

So far, 39.54% of the shares subject to the offer, or just over 30% of Cattolica's total capital have been tendered in the bid, which ends on Oct. 29, bourse data showed. With the shares already owned ahead of the offer, Generali now holds a stake in Cattolica of just under 54%, above the 50% plus one share threshold it has set as a condition of the offer.

Generali first moved on Cattolica last year, coming to its rescue with a 300 million euro investment after supervisors told the Verona-based insurer to bolster its finances.

The Trieste-based company became Cattolica's single largest shareholder with a 23.7% stake last year, relegating Warren Buffett's Berkshire Hathaway to second place.

Earlier last week Berkshire Hathaway tendered its 6.9% stake under the takeover offer.

To gain full control, with the goal of taking Cattolica private, Generali has offered 6.75 euros a share. The offer is conditional on it gaining control of at least 66.67% of Cattolica, a threshold Generali reserved the right to lower to 50% plus one share.

(Reporting by Andrea Mandala, editing by Giulia Segreti, Kirsten Donovan)