0600 GMT - The $6 billion volume for the U.S. Treasury's increased-volume long-end securities buyback operation sounds like a large number, but it is still relatively small compared with the U.S. Treasury debt outstanding, BondBloxx Investment Management's JoAnne Bianco says in a note. "Investors may have been looking for a stronger signal that Treasury was willing to meaningfully offset the supply pressures that have been pushing long-term yields higher," the senior investment strategist says. Instead, the Treasury's announcement appears to be more of a liquidity management tool than a meaningful change in Treasury's broader debt management strategy, she says.