The chairman of China Construction Bank, China’s biggest property lender, has unexpectedly retired under a raising concern on his possible involvement in corruption, people familiar with the matter said.

People close to the Chinese banking industry say the 58-year-old Mr. Zhang, whose predecessor was dismissed for bribery and later imprisoned, resigned for "personal reasons" and the board would meet in the next few days to discuss the resignation. Press officials at China Construction Bank refused to provide any comment. A spokesman for the China Banking Regulatory Commission, Li Shaoping, did not either confirm or deny that Mr. Zhang was leaving or whether there was a corruption investigation.

However, people familiar with the matter in Hong Kong say Mr. Zhang’s movements and activities have been monitored and restricted since last Thursday as part of an investigation by Chinese authorities into corruption, according to the Wall Street Journal. The case involves an alleged bribery related to the buying of information-technology equipment, though the charges have not been brought yet.

The case is likely to have a negative impact on oversea investment since foreign institutions are considering whether to invest hundreds of millions of dollars in China Construction Bank and the Bank of China, another of the Big Four commercial lenders planning to issues shares overseas.