The National Social Security Fund, ICBC's largest shareholder, sold 40.1 million Hong Kong-listed shares in the world's largest bank by market capitalisation at HK$6.074 each on March 1, according to the disclosure.

It marks the second time the fund has reduced its stake in ICBC after selling 15.296 million H shares at HK$6.30 each on April 9 last year, reducing its holding to 18.99 percent, data from the disclosure showed.