In case you missed it: US Treasury is increasing the size of liquidity support buyback operations for longer-dated securitiesThat was the big announcement that has gotten markets buzzing again this week. Essentially, the US Treasury is doubling the size of buybacks at the long-end of the curve. So, that adds more liquidity i.e. supply into the market after having seen 30-year yields surge to its highest since 2007 earlier in the week. As a result, the dollar got slammed down alongside bond yields while stocks and precious metals surged higher.The question now is, how significant is this change and will it be one to shift the structural outlook of not just the bond market but broader markets as well?Let's first address the impact of the announcement. The main point here is to bolster market liquidity and in that lieu, it definitely buys some relief for the long-end of the curve.However, that relief might just be short-term. What the US Treasury is doing here is no different than their recent steps to try and help Japan with the yen currency intervention. It's something different to try and get markets to react but it still does not address the underlying structural issues behind the scenes.The surge higher in 30-year yields in the US comes even after softer US data at the start of August. So, what does that tell us?It's a signal that rates are rising largely due to fiscal worries and also mounting inflation expectations. The latter is not helped by the prolonged situation in the Middle East, not least helping to underpin oil prices again.The other key takeaway is that it tells us that the US Treasury has seen yields go up to a level they don't like, hence feeling the need to step in and buy time essentially. But mind you, the developing backdrop in pushing rates higher is not to say is caused by some major market dislocation of any sort. It's pretty much a straightforward case as mentioned above.But now instead, markets are starting to come around to the idea that there is a "Bessent put" in place now.All that being said, I would argue that it all still comes down to the structural outlook of the market. Unless fiscal spending eases and inflation pressures cool, it would arguably be a matter of time before market players push back again.And I guess that's what the US Treasury is hoping for, with some support from the Fed in not positioning more hawkishly. And in due time, hopefully inflation expectations will drop should there be better developments in the Middle East.But unless that happens, expect the bond vigilantes to still have a good reason to come back into the market.As for the US Treasury committing to this decision, there will also be other key risks to be mindful of. That is largely tied to the idea of a "Bessent put" at the moment.That in itself might present some moral hazard and create some unintended overlap with monetary policy function. If the US Treasury continues to step in as it does, it could give investors a false sense of security and comfort in taking riskier and more leveraged positions. And we all know when shit hits the fan, things don't tend to turn out well in such circumstances. And this is the Treasury market we're talking about, so that's a bit of a hazard to say the least.Adding to that, stepping in on the long-end of the curve now directs the debt pressure to the short-end instead. If dealers are forced to absorb a much bigger amount of T-bill issuances instead (in needing to fund the buybacks), that risks draining excess cash in money markets. Think of the less talked about funding and repo markets. These are spots that typically function without any fuss from day to day but one small dislocation risks setting the whole financial system on fire. So to even start to shift some risks over to this side, is not something that might go down well when things start to really get dicey. This article was written by Justin Low at investinglive.com.