* Hang Seng index ends down 0.07%, trims early losses * HSTECH index falls as much as 4.95%, ends down 1.2% * SEC adopts measures which could delist Chinese companies * Monitoring concerns weigh as China reported to mull user data JV March 25 (Reuters) - Slumping dual-listed tech firms weighed on Hong Kong’s Hang Seng index on Thursday after the top U.S. securities regulator began implementing measures that could remove some foreign companies from American stock exchanges. The Securities and Exchange Commission (SEC) on Wednesday adopted measures under the Trump-era Holding Foreign Companies Accountable Act, which aims to remove Chinese companies from U.S. exchanges if they fail to comply with American auditing standards for three years in a row. The Hang Seng index finished down 0.07% at 27,899.61 points. It had slipped as much as 1.48% earlier, dragged down by a 4.95% drop in the Hang Seng TECH index on the SEC news. The TECH index trimmed losses to end the day down 1.2%. Chinese H-shares listed in Hong Kong fell 0.96%. Companies with U.S. listings led declines. JD.com lost 3.57%, Alibaba fell 3.91% and NetEase shed 2.25%. But investors had overreacted to the SEC news, said Alex Wong, director at Ample Finance Group in Hong Kong, adding that the move would have little overall impact on the city. “The major beneficiary of the news would be (exchange operator) Hong Kong EX, because most of the trading actually would be reallocated to Hong Kong eventually,” he said. Hong Kong Exchanges and Clearing jumped 3.17%, leading a 1.21% gain in the financials sub-index. In mainland China, the blue-chip CSI300 index edged down 0.05% to a more than three-month low, and the Shanghai Composite Index dipped 0.1%. Tech firms also faced pressure from reports that China is considering creating a state-backed joint venture with domestic tech firms to oversee user data they collect. “The market is going through a ‘sell first, ask questions later’ phase ... investors think (authorities) want to use the big tech firms to monitor citizens,” said Dave Wang, portfolio manager at Singapore’s Nuvest Capital, adding some users may leave such platforms. Chinese apparel and clothing companies, however, surged over a social media storm on Xinjiang cotton. ANTA Sports Products Ltd soared 8.40% after it said it will continue to use Chinese cotton, including from Xinjiang. The United States, the European Union, Britain and Canada on Monday imposed sanctions on Chinese officials for alleged human rights abuses in Xinjiang. China retaliated with sanctions on European lawmakers and institutions.