The Allstate, a personal lines insurer, has agreed to acquire White Mountains Insurance Group's businesses Esurance and Answer Financial for $700m.

Esurance is a provider of online auto insurance quotes, and sells personal auto insurance directly to customers online and through 24-7 call centers.

Answer Financial is an independent personal insurance agency in the US. It serves self-directed consumers who seek a choice among insurance companies. Customers are given quote comparisons and assistance in choosing from 20 brand-name insurance companies.

The acquisition price includes the tangible book value of the entities acquired at close and is expected to be about $1bn.

Allstate president, chairman and CEO Thomas Wilson said Esurance will expand Allstate’s ability to serve customers that are more self-directed but still prefer a branded product.

"Answer Financial will strengthen our offering to individuals who want to be offered a choice between insurance carriers and are brand-neutral," Wilson said.

The transaction, subject to approval, is expected to close in the fall 2011.