By Joanne Chiu

Hong Kong's status as a venue for major Chinese technology companies got a boost Thursday, as shares in mobile-games group NetEase Inc. jumped on their debut in the city, while e-commerce company JD.com Inc. fixed a price for its own US$3.9 billion offering.

The duo are following Alibaba Group Holding Ltd. in securing secondary listings close to their home market, and the deals come as tensions between the U.S. and China widen to include financial-markets issues. The Senate in May passed a bill that could kick Chinese companies off U.S. stock exchanges unless American authorities can inspect their audits.

In addition, the listings are proceeding as the prospect of a Beijing-imposed national-security law raises questions about the city's future as an international financial and commercial hub. Robust demand for the new shares has buoyed the Hong Kong dollar, prompting official intervention to stop the pegged currency strengthening too much.

On Thursday, shares in NetEase Inc. closed 5.7% higher, after its Hong Kong stock traded for the first time following a US$2.7 billion fundraising. Meanwhile, people familiar with the matter said JD.com has guided investors it plans to price its stock sale at 226 Hong Kong dollars (US$29.15) a share -- implying a total value of about US$3.9 billion, ahead of a trading debut in a week's time.

The offerings are a boost for exchange-operator Hong Kong Exchanges and Clearing Ltd., which in 2018 revamped its rules to allow founder-friendly corporate-governance structures, such as shares with unequal voting rights.

With Alibaba, JD, Meituan Dianping, NetEase and Tencent Holdings Ltd., the Hong Kong market will be home to five Chinese tech firms with market valuations of more than US$50 billion each.

"While a U.S. listing enables issuers to build a profile with international investors, a potential second listing in Hong Kong can help to further broaden their shareholder base, such as to include day-to-day customers of their apps and services," said Johnson Chui, head of equity capital markets for Asia Pacific at Credit Suisse.

The bank is one of three sponsors for the NetEase deal. Mr. Chui said listing-rule changes and moves to allow companies with super-voting rights into the benchmark Hang Seng Index have increased the appeal of a secondary listing in Hong Kong for U.S.-listed Chinese companies.

A Hong Kong listing also means investors can trade nearly 24 hours a day, given the different trading hours for U.S.-listed American depositary receipts and for Hong Kong-listed shares, he said.

Depositary receipts in both JD.com and NetEase have soared this year, giving the companies market valuations of about US$86 billion and US$55 billion, respectively. For both deals in Hong Kong, bankers have the option to increase the eventual deal size by 15%.

JD.com's shares will carry the ticker 9618.HK, and as is customary for follow-on share offerings, they were priced slightly cheaper than the shares outstanding. The offer price represents a 3.9% discount to the price implied by Wednesday's closing price for JD.com's American depositary receipts. Each ADR is equivalent to two ordinary shares in Hong Kong.

The share sales have helped boost the local currency. So far in June the Hong Kong Monetary Authority has sold HK$27.4 billion for U.S. dollars, keeping the city's currency from strengthening beyond 7.75 per dollar.

In a note to clients dated Thursday, analysts at China Renaissance said other large, U.S.-listed Chinese firms eligible to list in Hong Kong included Baidu Inc., TAL Education Group, ZTO Express (Cayman) Inc., New Oriental Education & Technology Group Inc., and Trip.com Group Ltd.

Write to Joanne Chiu at joanne.chiu@wsj.com