While Shanghai, Beijing and Shenzhen remain the top three financial centers among Chinese mainland cities, the gap between Shenzhen and the other two is widening, according to the China Financial Center Index released by a Shenzhen-based think tank on Friday.

The three cities are taking the lead not only in terms of overall strength in the financial industry, but also in the speed of growth, the latest report by the China Development Institute shows.

Shanghai topped the list, scoring 222.9; Beijing received178.4, and Shenzhen scored103.6, according to the report.

However, despite remaining in third place, Shenzhen is lagging increasingly behind the top two cities, with the gap between Shenzhen and Shanghai widening from 37.8 in 2009 to 119.3 in 2017.

Shenzhen's growth in the financial industry has also been slower compared with the other two. Since 2009, Shanghai has grown 122.9 percent, Beijing 99.9 percent and Shenzhen 66.6 percent, the report states.

"With housing prices keep rising, Shenzhen has become the one among 31 surveyed cities with the highest housing price-to-income ratio," Liu Guohong, director of the Finance and Modern Industry Research Center at CDI, said.

"This has significantly increased living cost and exerted a passive impact on attracting financial talents."

CDI, which has published the index annually since 2009, bases its findings on 88 indicators in four aspects: financial industry performance, financial institutions strength, financial market scale and financial ecological environment.

The other cities in the top 10 list are Guangzhou, Tianjin, Chengdu, Hangzhou, Chongqing, Nanjing and Suzhou.