BEIJING - Lock-up shares worth 30.1 billion yuan ($4.9 billion) will become eligible for trade on China's stock markets?this week.

A total of 1.7 billion shares from 20 companies will be tradable on the Shanghai and Shenzhen bourses from May 18 to 22, down from 68.3 billion yuan shares unlocked between May 11 and 15, according to Southwest Securities.

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

Pengxin International Mining Co Ltd will see non-tradable shares worth around 9.6 billion yuan become tradable on May 22, the largest amount of such shares to hit the stock market in the period.

Chinese shares closed lower on Friday over concerns of more initial public offerings. The benchmark Shanghai Composite Index fell 1.59 percent to finish at 4,308.69 points.