A host of forces has combined to push short rates to the zero bound. The roll off of SFP bills to tweak the debt ceiling target date started the flood. The FDIC fee increase for April 1 added pressure through repo. PDs seem reluctant to apply balance sheet to FF - IOER arbitrage for smaller pickup. Technical in nature, we believe this still to be an historic marker.
As a rule, for fixed income, if you can't short it at zero it has ceased to matter. The switch from supply to OMO has lifted prices and we will look to set tactical shorts over the next 48 hours. The level of rates is not the problem so holding it at zero cannot be the solution. The destruction of the money market is counter productive to the Fed's coming need for it. Reverses of the size needed to execute even marginal restraint will be messy affairs.