Under Joseph Sullivan, who became CEO in February 2013, Legg Mason has sold several businesses, created new products and bought other small investment firms as it tries to move beyond a long period of net quarterly withdrawals by customers.

Headquartered in Edinburgh, Scotland, Martin Currie is a good fit as investors put more money into international stocks, Sullivan said in an interview. "You have to have a global investment capability that reflects that demand," he said.

Sullivan said he will keep looking for deals, for instance one that would allow Legg Mason to sell alternative investment products in areas including energy or infrastructure. But finding such an acquisition could take some time, he said.

Legg Mason's Australian Equities unit with $2.5 billion (1.47 billion pounds) in assets under management will become part of Martin Currie after the deal closes.

Privately held Martin Currie, which has about $9.8 billion (5.77 billion pounds) of assets under management, runs equity portfolios for clients across Europe, the Middle East, Asia and Australia.

Terms of the deal were not disclosed.

The deal is expected to add slightly to Legg Mason's earnings in the first year and is expected to close during the fourth quarter of 2014, the purchaser said in a statement.

Legg Mason of Baltimore said in March it would buy privately held QS Investors and merge it with two other business units, aiming to build sales to institutional clients and retail investors.

Legg Mason was advised by JP Morgan Securities and Dechert LLP. Martin Currie was advised by UBS Investment Bank.

Legg Mason's shares were up 2.1 percent at $51.72 on Thursday morning on the New York Stock Exchange. They have gained about 16 percent since the beginning of the year to Wednesday close.

(Reporting by Neha Dimri in Bangalore and Ross Kerber in Boston; editing by Rodney Joyce, Sriraj Kalluvila and Matthew Lewis)

By Neha Dimri and Ross Kerber