ADRs in Focus: Asian banks mixed on M&A

The deal creates Australia's biggest financial service company in terms of market capitalization. The combined companies will have around 10 million customers.

Citi Investment Research analyst Craig Williams said there's still an opportunity for another bank to raise the price, despite a two-week period of exclusivity, where the banks will negotiate the terms of an agreement.

However, Williams expects Westpac's bid for St. George Bank to prevail given its premium rating, among other factors.

Westpac Banking declined $3.75, or 3.1 percent, to $117.58.

Elsewhere in the sector, ICICI Bank Ltd. rose 28 cents to $42.50. HDFC Bank Ltd. declined $1.23 to $106.48, and Mizuho Financial Group Inc. rose 7 cents to $10.01.

The Bank of New York Asia ADR Index -which tracks shares of companies based in China, India, Australia and others -lost 0.30 points to 163.44 and has declined around 2 percent so far this year. ADR stands for American Depositary Receipt, which is a security designed to allow U.S. investors to trade shares of companies based overseas.

Overseas, Asian markets were mixed. The earthquake that ripped through central China's Sichuan province weighed on stocks in China, but investors in Tokyo and Hong Kong remained confident that the disaster would have a limited effect on the economy.