Chinese banking stocks listed in Hong Kong tumbled on Wednesday after Goldman Sachs downgraded ratings on some Chinese banks in a report and raised questions over the whole sector.

Hong Kong's Hang Seng Mainland Banks Index was down more than 3%, set for its biggest daily drop in eight months.

Goldman Sachs analysts downgraded Agricultural Bank of China from "Neutral" to "Sell", Industrial and Commercial Bank of China and Industrial Bank from "Buy" to "Sell" in a report on Wednesday.

Agricultural Bank of China shares fell 2.6%, while Industrial and Commercial Bank of China and Industrial Bank shares were down 1.9% and 0.5%, respectively.

The Wall Street bank said that Chinese banks cannot maintain a good balance of provisions, capital and dividends at the same time on squeezed earnings. (Reporting by Shanghai Newsroom; Editing by Himani Sarkar)