China's four state-owned commercial banks announced Thursday that they will cut interest rates on existing mortgages for first-home loans.

The adjusted interest rates will be effective from Sept. 25, the Industrial and Commercial Bank of China, the Agricultural Bank of China, the Bank of China and the China Construction Bank said in statements.

The move followed a decision by China's financial watchdogs last week to optimize housing credit policies, in a bid to reduce interest expense for mortgage borrowers and help spur consumption and investment.

According to analysts, this lowering of mortgage rates will benefit about 40 million borrowers.