SHANGHAI (Reuters) -Mainland China stocks advanced on Thursday, with the Shanghai benchmark closing at a decade high level, driven by hefty gains in fintech and stablecoin-concept shares after a Reuters report signalled a major shift in Beijing's stance on digital assets.

** At the close, the Shanghai Composite index was up 0.13% at 3,771.10 points, the loftiest close since August 2015, while the blue-chip CSI300 index gained 0.39%.

** Fintech and stablecoin-concept shares were among the biggest winners in morning deals, after Reuters reported, citing sources, that China is considering allowing the usage of yuan-backed stablecoins for the first time to boost wider adoption of its currency globally.

** China's plan for the usage of stablecoins, if approved, would mark a major shift in its approach towards digital assets. The country banned cryptocurrency trading and mining in 2021 due to concerns about the stability of the financial system.

** The CSI Fintech Theme index advanced 0.78%, while Brilliance Technology Co jumped 12.59% and Tansun Technology Co leapt 4.75%.

** Chinese shares have been rising, supported by easing trade tensions between the world's two largest economies and improved liquidity conditions, and as investors shift out of bonds and into stocks, traders and analysts said.

** James Wang, head of China strategy at UBS Investment Bank research, said rising retail participation could be one of the drivers underpinning the recent stock rally.

** "Retail flows may have been one of the drivers with trading volume up 80% year-on-year on the A-share and margin financing balance outstanding also rising sharply," Wang said.

"As retail participation typically increases following stronger performances for the A-shares, it would seem that A-share offers better upside potential."

** In Hong Kong, the benchmark Hang Seng index slipped 0.24% at 25,104.61 points, while the Hang Seng China Enterprises index fell 0.43% to 8,974.77.

** Around the region, MSCI's Asia ex-Japan stock index was firmer by 0.2%, while Japan's Nikkei index closed down 0.65%.

(Reporting by Shanghai Newsroom; Editing by Mrigank Dhaniwala)