Travelers is a diverse consumer and business insurance firm and Assurant owns a number of specialty insurance subsidiaries.

FORBES: Connect

Although they approach the business of managing risk more directly than, say, an insurance firm, their employees do not don uniforms or wield guns.

ECONOMIST: Corporate security

Citigroup, which was formed by a merger last year of Citibank and Travelers, an insurance-and-stockbroking firm, already does just about every sort of financial business.

ECONOMIST: Killing Glass-Steagall

The company's chief executive Sam Ghosh said last month that the firm was in talks with potential investors to sell a similar stake in its general insurance business.

BBC: Anil Ambani

Aetna, an old Connecticut insurance firm, was trying to shift from low-growth financial services into the booming managed-care business.

ECONOMIST: Managed health care: Aetna implodes | The