BEIJING, Jan. 26 -- Lock-up shares worth 39.54 billion yuan (6.48 billion U.S. dollars) will become eligible for trade next week in China.

The volume marks a 26-percent rise from last week, according to information from the Shanghai and Shenzhen stock exchanges.

Altogether, 21 listed companies on the two stock exchanges will see their lock-up shares released onto capital markets next week.

Under the mainland's market rules, major shareholders of non-tradable stocks are subject to one or two years of lock-up before they are permitted to trade.

Of all the companies with non-tradable shares becoming tradable next week, Inner Mongolia Baotou Steel Union Co.,Ltd ranks first with its non-tradable shares worth 6 billion yuan.