(Adds market activity, details on Biden tax proposal, analyst comment) By Ross Kerber April 22 (Reuters) - U.S. Treasury yields fell back on Thursday on news that President Joe Biden will propose a tax hike for high earners, after climbing in morning trading. The benchmark 10-year yield was down less than 1 basis point for the session, at 1.5556%, after having risen above 1.587% just after noon. Biden will propose raising the marginal income tax rate to 39.6% from 37% and nearly doubling taxes on capital gains to 39.6% for people earning more than $1 million, sources familiar with the matter told Reuters. The money would fund major investments in child care and paid leave for workers. Wall Street"s main indexes hit session lows as the tax news hit. Guy LeBas, chief fixed income strategist for Janney Capital Management, said Treasuries seemed to move in step with stocks as investors bailed out of equities that would lose some of their tax advantages for people in the top income brackets. LeBas cautioned, however, that the proposal faces many hurdles and potential compromises, one reason the benchmark yield remained well within the range between 1.528% and 1.633% it has held since last week. "There"s a lot of road between here and law," he said. Investors are looking ahead to guidance from the Federal Reserve"s meeting next week, on Tuesday and Wednesday, although the U.S. central bank"s Federal Open Market Committee is not expected to make meaningful adjustments to policy. Fewer Americans filed new claims for unemployment benefits last week, U.S. Labor Department data showed on Thursday, suggesting that layoffs were subsiding and strengthening expectations for another month of blockbuster job growth in April as a re-opening economy unleashes pent-up demand. Jim Vogel, FHN Financial interest rate strategist, said this week"s relatively small movement in yields reflected investors" focus on trading specific maturities rather than making bets about trends across the whole yield curve while awaiting guidance from the Fed. "It"s more dangerous to express macro views across the bond market, when each spot trades in its own place. It"s not a unified market," Vogel said. The Biden administration on Thursday pledged to slash U.S. greenhouse gas emissions by 50%-52% from 2005 levels by 2030, a target it hopes will spur other big emitter countries to raise their ambitions to combat climate change. A closely watched part of the U.S. Treasury yield curve measuring the gap between yields on two- and 10-year Treasury notes, seen as an indicator of economic expectations, was at 140 basis points, about a basis point lower than its close on Wednesday. The two-year U.S. Treasury yield, which typically moves in step with interest rate expectations, was up less than a basis point at 0.1513%. April 22 Thursday 2:22PM New York / 1822 GMT Price Current Net Yield % Change (bps) Three-month bills 0.0225 0.0228 0.000 Six-month bills 0.035 0.0355 -0.002 Two-year note 99-243/256 0.1513 0.002 Three-year note 100-42/256 0.3196 0.000 Five-year note 99-190/256 0.8033 0.003 Seven-year note 100-24/256 1.2358 -0.002 10-year note 96-24/256 1.5556 -0.008 20-year bond 95-228/256 2.1302 -0.019 30-year bond 92-12/256 2.2422 -0.021 DOLLAR SWAP SPREADS Last (bps) Net Change (bps) U.S. 2-year dollar swap 12.00 0.25 spread U.S. 3-year dollar swap 13.50 0.25 spread U.S. 5-year dollar swap 9.25 0.50 spread U.S. 10-year dollar swap -0.75 0.25 spread U.S. 30-year dollar swap -27.00 0.00 spread (Reporting by Ross Kerber in Boston; editing by Barbara Lewis and Leslie Adler)