Nio rose 9.55 percent by the close of the Hong Kong stock market today, giving it a 34 percent gain since May 13.

Just two months after its secondary listing in Hong Kong, Nio (NYSE: NIO, HKG: 9866) has received the green light to be included in the city's two major stock indices.

Nio will be included in the Hang Seng Composite Index as well as the Hang Seng Tech Index, with the changes effective Monday, June 13, according to a quarterly review released today by the Hang Seng Indexes Company Limited (HSI).

The Hang Seng Composite Index, which covers the top 95 percent of the total market capitalization of securities listed on the Main Board of the Hong Kong Stock Exchange, provides a comprehensive indicator of the Hong Kong market, according to information on the HSI's website.

The index is calculated using the liquid market capitalization weighting method and can be used as a benchmark for issuing index funds, mutual funds and performance measures.

With the addition of Nio, the number of constituent stocks in the Hang Seng Composite Index will increase from 516 to 517. Nio was listed in Hong Kong on March 10.

The Hang Seng Composite Index closed today up 2.74 percent to 3,129.56 points. So far this year, it was down 13.7 percent.

(Hang Seng Composite Index year-to-date performance.)

In addition to the Hang Seng Composite Index, Nio was included in the Hang Seng Tech Index, and ASM Pacific Technology Ltd was removed to maintain the number of constituents at 30.

The Hang Seng Tech Index closed today up 4.74 percent and accumulated a 25 percent decline so far this year.

On February 18, the HSI announced that Nio's local peers Xpeng Motors (NYSE: XPEV, HKG: 9868) and Li Auto were added to the Hang Seng Tech Index, effective Monday, March 7.

Nio's weighting in the Hang Seng Tech Index will be 0.52 percent, lower than Li Auto's 2.13 percent and Xpeng's 1.11 percent, according to information released today by the HSI.

This reflects Nio's lower liquidity factor, as it has been listed in Hong Kong for a relatively short period of time. Nio's liquidity factor is 7, compared to Li Auto's 30 and Xpeng's 20.

Nio's weighting in the Hang Seng Composite Index has not been released. Xpeng and Li Auto are also included in the index.

Joining the indices means that they will have access to passive inflows from those ETFs that track the index, even though the Hong Kong market is far less liquid than the US market.

By the close of the Hong Kong stock market, Nio was up 9.55 percent, bringing its gain since May 13 to 34 percent.