Asian stocks rose on Thursday after the U.S. Treasury said it would at least double its buyback operations for longer-dated debt to $4 billion or more per operation from September. The move helped lower the 30-year Treasury yield by about 1 basis point to 5.18% and the 10-year yield to around 4.63%, easing pressure after the 30-year rate reached its highest level since 2007. South Korea's KOSPI jumped 6.4% as semiconductor shares rebounded, with SK Hynix surging 13.1% after announcing a 40 trillion won ($28.6 billion) share buyback and cancellation program. Japan's Nikkei 225 rose 1.1%, while Chinese technology stocks also advanced. Analysts said the Treasury action could temporarily improve liquidity at the long end of the bond market, although fiscal pressures may keep term premiums elevated. Oil remained a headwind, with Brent crude near $92 a barrel and on track for a fifth consecutive gain amid increased U.S. pressure on Iran and uncertainty over reopening the Strait of Hormuz.