Hong Kong's Dah Sing Banking and U.S. buyout firm Carlyle signed an agreement on Thursday to buy a 24.99 percent stake in Chongqing Commercial Bank, the mid-sized Chinese lender said. Carlyle and Dah Sing would pay about $100 million.

Dah Sing will buy a 17 percent stake in the bank -- which will have total year-end assets of 36 billion yuan and deposits of 28.5 billion yuan ($3.65 billion), and Carlyle will take 7.99 percent, the bank said in a statement.

The stake sale to overseas investors was part of measures aimed at transforming the Chinese lender into a retail-focused bank aiming eventually to list overseas, the statement said.

"Chongqing bank will bring in advanced business philosophy, mature techniques and managerial know-how from the strategic investors in order to realise a faster and better development of the company," it said.

It gave no value for the deal, but said the investors are buying the stake from a local firm, Yufu, at a price/book ratio of 1.87 times, higher than recent stake deals in other similar Chinese city commercial banks.

If the deal is approved by Chinese regulators, it would be the first direct investment by U.S.-based Carlyle in China's banking sector. Carlyle recently quit a Citigroup-led consortium to buy a controlling stake in Guangdong Development Bank last month for $3.1 billion.