(Yicai Global) July 6 -- The first one-year lockup period of CNY188.7 billion (USD26.8 billion) worth of shares trading on Shanghai's Star Market will be lifted on July 22, which has prompted the bourse to announce new rules to avoid wider sell-offs.

The headline figure makes up about 70 percent of the 24 related companies' market caps as of their closing prices on July 3, according to Wind data. Those firms were the first to start trading on the tech board on July 22, 2019. Five of them will see more than 80 percent of their market values unlocked.

On July 3, the Shanghai Stock Exchange introduced new rules on Star Market investors. First, pre-IPO investors cannot sell the equity for less than 70 percent of its market price. Second, the buyer has to hold onto the asset for six months.

Those companies whose share prices have surged over the year could experience stock price corrections as investors eye gains, an insider told Yicai Global. Most of those who bought the equities before trading started were venture capital funds, followed by investment companies and individual domestic investors, according to Shenwan Hongyuan.

The bourse has another card up its sleeve. On the first anniversary, the SSE will launch the SSE Star 50 Index, the first stock benchmark to track the Nasdaq-style board's biggest companies, which should make it easier for investors to follow the board's general performance while easing selling pressures, according to Shenwan Hongyuan Securities's report.

"The diversified shareholding reduction methods and the outlook for incremental capital entering the market are all expected to ease the downward pressures on stock prices on the Star Market," Shenwan Hongyuan added.

Finishing the lockup period should not affect the market too much because of the SSE's regulations that should curb institutional investors' selling aspirations, Yang Delong, chief economist at First Seafront Fund Management told Yicai Global.

Editor: Tang Shihua, Emmi Laine