o sell Chinese shares have found themselves locked out of 72 percent of the market.

At least 1,331 companies have halted trading on mainland exchanges, freezing $2.6 trillion of shares, or about 40 percent of the country’s market capitalization. Another 747 fell by the 10 percent daily limit on Wednesday, making it all but impossible to find buyers at the prevailing price.

The suspensions, which cast doubt on authorities’ pledge to give markets a greater role in the world’s second-largest economy, mean that the Shanghai Composite Index’s 5.9 percent tumble on Wednesday was probably understated. Investors who got stuck in their positions are turning elsewhere to raise cash, fueling the biggest drop in a month in Chinese government bonds and helping send Hong Kong’s Hang Seng Index to a 5.8 percent tumble.

“It’s absurd, stopping trading just because they don’t want stocks to fall,” said Tsutomu Yamada, a market analyst at Kabu.com Securities Co. in Tokyo. “They’re going all out in trying to stop stocks from falling but it’s not working.”

Chinese equities have lost more than $3.5 trillion of value in less than a month as traders liquidated leveraged bets at an unprecedented pace. Foreign investors extended a record three-day exodus on Wednesday as some said government meddling is making matters worse.

Panic Levels

“Trading halts will affect investor confidence,” said Bernard Aw, a strategist at IG Asia Pte Ltd. in Singapore. “Individual traders will still offload the counters when trading resumes, unless there is a considerable change.”

On the Shanghai exchange, 365 companies suspended trading, equivalent to 33 percent of all listings. A further 992 were halted in Shenzhen, or 56 percent of the total.

The selloff has overwhelmed efforts by policy makers to restore confidence. China Securities Finance Corp., which manages the nation’s short selling and margin trading, is seeking at least 500 billion yuan ($80.5 billion) to shore up equities, people familiar with the matter said Wednesday. The central bank said the same day it would provide “ample liquidity” to the market and the government ordered state-owned companies not to sell shares.

The authorities have “not only failed to stabilize the market, they have actually increased panic levels,” Alex Wong, Hong Kong-based asset-management director at Ample Capital Ltd., which oversees about $129 million, said by phone. “We are reducing exposure, raising cash levels and trying to stay out of the market.”

The Shanghai Composite has tumbled 32 percent from its June 12 peak, while the smaller Shenzhen Composite Index has lost 40 percent. The outstanding balance of margin debt on the Shanghai bourse fell by 93.5 billion yuan Tuesday, the most since the data began in 2010.

“The selling in China will continue for some time,” said Audrey Goh, an investment strategist at Standard Chartered Plc in Singapore. ‘The suspension in trading of a number of companies in mainland exchanges isn’t helping.’’