Update: Updated with Hong Kong stock market performance at the close of trading.

Nio was up nearly 8 percent in Hong Kong after rising nearly 15 percent at one point. Xpeng and Li Auto were both up about 10 percent.

Stocks of major electric vehicle (EV) companies trading in Hong Kong saw significant gains, as the overall market rebounded.

By the market close, Nio (NYSE: NIO, HKG: 9866) was up nearly 8 percent in Hong Kong after rising nearly 15 percent at one point. Xpeng Motors (NYSE: XPEV, HKG: 9868) and Li Auto (NASDAQ: LI, HKG: 2015) were both up about 10 percent.

Hong Kong stocks were higher overall today, with the Hang Seng Index up 2.1 percent and the Hang Seng Technology Index up 5.4 percent. The Chinese mainland's A-share market is closed today for the Qingming Festival, or Tomb-Sweeping Day.

The stock market performance may be largely due to the release of new draft regulations by China's securities regulator that hint at positive surprises on audit papers for Chinese companies listed abroad.

The China Securities Regulatory Commission (CSRC) issued an announcement on April 2 that it will revise its regulations on confidentiality and file management for Chinese companies listed abroad, originally issued in 2009, and seek public comments on the new text. The Chinese public has until April 17 to provide feedback.

Most notably, the new regulations will remove the following statement from the previous version:

On-site inspections shall be conducted primarily by Chinese regulators or rely on the results of inspections by Chinese regulators.

The CSRC firmly supports companies to choose their own listing locations according to their own wishes, and the deletion of the above statement is based on the international practice of cross-border audit and regulatory cooperation, it said.

"This reflects the consistent openness of Chinese regulators to cross-border audit and regulatory cooperation and is in line with relevant international practices, and will provide institutional safeguards for the safe and efficient conduct of cross-border regulatory cooperation, including joint inspections," the CSRC said.

From a fundamental perspective, China's major new energy vehicle (NEV) companies all recently reported strong March sales.

Xpeng delivered 15,414 units in March, Li Auto 11,034 units and Nio 9,985 vehicles. BYD sold more than 100,000 NEVs in March for the first time and announced that the company has stopped producing fuel vehicles.

According to a picture shared by a large number of Weibo car bloggers on Sunday, a vehicle suspected to be the new Nio SUV ES7 was seen in a parking lot.

China's securities regulator issues new draft regulation, hinting at positive surprise on audit issues