A view of China Securities Regulatory Commission, the securities regularor,?in Beijing on May 6, 2015. [Photo/VCG]

Regulator is said to first judge market sentiment and then calibrate the supply of new shares

China's market for initial public offerings is the hottest it's ever been, thanks to the securities regulator.

The 62 new stocks that have completed their first month of trading this year soared 420 percent on average in the span, the steepest such rally on record, data compiled by Bloomberg show.

For a clue as to why: the average size of this year's offerings has dwindled to $88 million, the smallest since 2005.

While huge returns on mainland IPOs are not new, the numbers are getting even more eye-watering as the China Securities Regulatory Commission seeks to stabilize the nation's $6.1 trillion equity market.

Officials asked arrangers and companies to limit their deal sizes in the first half to avoid an oversupply of shares, according to people with knowledge of the matter.

A proposed registration system that would have given firms more flexibility on IPO pricing and timing has been delayed.

An investor walks past an electronic display showing prices of shares at a brokerage house in Fuyang city, east China's Anhui province, Jan 6, 2016. [Photo/IC]

The Shanghai Composite Index is down 16 percent this year, one of the world's biggest declines.

"Regulators are carefully watching and testing market reactions as they approve IPOs," said Dai Ming, a money manager at Hengsheng Asset Management Company in Shanghai. "They tend to tighten approvals when the market slumps and release more deals when sentiment improves."

More than 800 companies have filed IPO applications and are waiting for approval, according to the CSRC's website.

The 78 completed sales this year compare with 219 in all of 2015, and the value of the deals is about a quarter of the 2015 amount, Bloomberg data show.

Wuxi Honghui New Materials Technology Company was one of the lucky ones, raising $39 million in June. The shares soared 553 percent in their first month on the Shenzhen exchange, and are now up 580 percent from their IPO price.

The company is typical of Chinese IPOs in that it priced at a multiple below the market average－nearly all initial shares sold in the past two years were valued at less than 23 times profit, data compiled by Bloomberg show.

Wuxi Honghui's listing valuation of 22.98 times earnings compares to an average multiple of 43.3 for firms in the chemical products industry, the company said in a June 17 filing.

"Investing in A-share IPOs is highly profitable because regulators keep prices low," said Hao Hong, chief strategist at Bocom International Holdings Company in Hong Kong. "The odds of winning initial shares are falling as returns surge."

For the 13 stocks that started trading last month, the average chance for a retail investor to be allocated any shares in an offering was 0.04 percent, data compiled by Bloomberg show.

The CSRC has been signaling a tougher stance on letting companies list in China, warning brokerages last month to improve their standards when helping clients raise money. The regulator is also said to be considering measures to curb the flow of overseas-traded Chinese companies seeking backdoor listings on the mainland.

As the market stabilizes, the CSRC is set to approve bigger deals for the second half, the people familiar with the matter said. Bank of Jiangsu Co started trading Aug 2 after raising $1.1 billion in the biggest IPO this year. China Film Co Ltd saw a rise of 44 percent in its stock prices on its first trading day on August 9.

Bank of Jiangsu was the first A-share banking IPO since August 2010, data compiled by Bloomberg show. Lenders that received the CSRC's initial approval more than six months ago and are still waiting for a listing slot include Bank of Hangzhou, Bank of Shanghai and Jiangsu Jiangyin Rural Commercial Bank.

Some companies have gone to Hong Kong instead. Postal Savings Bank of China, one of the few State-owned giants remaining unlisted, is preparing for an $8-billion IPO this year.

While IPO approvals are hard to come by, regulators appear more lenient towards listed companies selling additional shares. Companies have completed more than 320 additional offerings on the Chinese mainland this year, raising $99 billion.

Bloomberg