BEIJING, May 11 -- The total value of lock-up shares becoming eligible for trade on China's stock market this week will rise slightly from the previous week, according to the country's two stock exchanges.

From Monday to Friday, 25 listed companies on the Shanghai and Shenzhen stock exchanges will see shares worth 19.4 billion yuan (3.15 billion U.S. dollars) released to the market after lock-up agreements expire.

The amount is slightly higher than the total value of 18.3 billion yuan that became tradable during the previous week.

Under China's market rules, major shareholders of non-tradable stocks are subject to a lock-up period of one or two years before they are permitted to sell their shares.

A rise in newly unlocked shares will put some downward pressure on the market as it means an increase in stock supply.