French reinsurer Scor SE spurned an 8.3-billion-euro ($9.6 billion) unsolicited takeover offer from its biggest shareholder, Covea, which said it’s still interested in pursuing a deal. Scor shares climbed the most in almost a decade.

Covea, a French mutual insurer that already has an 8.2 percent stake in Scor, said Tuesday that it offered to buy the remaining stock for 21 percent more than the company’s previous closing price. Scor responded that the bid is “fundamentally incompatible” with its strategy of staying independent.

Covea said that it withdrew the offer after Scor’s board met Thursday and refused to enter talks, but “reiterates its interest in a friendly transaction with Scor.” The other shareholders in Scor will get a chance to have their say at an investor day in Paris on Wednesday.

An acquisition of Scor would help Covea almost double its premium income and diversify its business beyond home, auto, life and health insurance coverage. Insurers and reinsurers have become popular acquisition targets, both for competing firms and private-equity buyers, who are targeting such assets in search of higher returns.

Axa SA, the largest French insurer, earlier this year agreed to purchase XL Group Ltd. for $15.3 billion. Apollo Global Management has increased its stake in reinsurer Catalina Holdings Bermuda Ltd. amid a broader insurance push, and Carlyle Group has been expanding its team to do more deals in the sector.

Attractive Valuations

Pricing pressure in the reinsurance industry is weighing on profits at companies like Scor, overshadowing a drop in natural-catastrophe claims. Still, an earnings stream is emerging in European reinsurance that should be less cyclical than in the past, and valuations in the sector look “highly attractive,” JPMorgan Chase & Co. analyst Edward Morris wrote in a note Aug. 29, upgrading Scor to overweight.

Scor climbed as much as 10 percent to 39.15 euros, below the bid price of 43 euros, and was up about 9 percent as of 1:30 p.m. in Paris. Before Tuesday, the shares had gained 5.7 percent this year, outpacing the 1.7 percent gain by the Stoxx Europe 600 Index.

The offer was to be financed with existing resources and with committed debt provided by Barclays Plc and Credit Suisse Group AG, Covea said. Thierry Derez, Covea’s chief executive officer, sits on Scor’s board of directors.

Covea is an unlisted insurer whose brands include GMF, MAAF and MMA, and most of its business is in France. The deal would increase Covea’s premium income to more than 30 billion euros.