Northbrook, Ill.--Allstate Corp., the nation's largest publicly held insurance company, has completed its $1.1 billion acquisition of American Heritage Life Investment Corp., the third largest workplace insurance marketer in the U.S. American Heritage shareholders will receive $32.25 for each share, receivable in Allstate shares, cash or a combination. The pact will give Allstate greatly expanded reach into the workplace insurance marketing arena. American Heritage's product line centers on disability and health insurance. The workplace insurance market is expected to grow 10% to 15% annually over the coming decade, according to Allstate research. Allstate's marketing plans are still in development.