NEW YORK—American International Group Inc.'s Chartis Inc. unit is realigning its geographic structure to better serve clients, Chartis CEO Peter Hancock said Tuesday.

The new regional organization brings with it senior management changes at the global property/casualty insurer as well.

“The purpose is to streamline our senior management team and simplify the way in which we manage what is a very broad franchise,” Mr. Hancock said. He noted that New York-based Chartis operates in more than 90 countries, and that more than half of its business comes from outside the United States.

“Having a streamlined matrix management structure is essential if we are going to reach our clients around the world with the expertise they need in a timely manner,” he said.

The new regional alignment replaces four geographic regions with three: the Americas; Asia; and Europe, the Middle East and Africa. Mr. Hancock said that within the new structure, three countries have been identified within each of the regions as being of particular strategic significance: Vietnam, Indonesia and China within Asia; India, Turkey and the United Arab Emirates in the EMEA; and Brazil, Mexico and Colombia in the Americas.

Mr. Hancock said growth economies now represent about 10% of Chartis' net premium written, and that the insurer expects that to grow to about 15% by 2015. He noted that last year, Chartis' total net premium written was $33 billion.

Robert Schimek, Chartis' chief financial officer, has been named president and CEO of EMEA. Deputy chief financial officer James Bracken succeeds Mr. Schimek as CFO.

Peter Eastwood, president and CEO of U.S. and Canada, becomes president and CEO for the Americas, which includes the United States, Canada, Latin America and Bermuda. Jose Hernandez, president and CEO of the Far East Region, becomes president and CEO of the Asia region.

In addition, Alexander Baugh, who had been president and CEO of Europe, will become Chartis' chief risk officer.

AIG reorganized Chartis last year and named Mr. Hancock CEO of the unit.