US sold 6-week bills at a high rate of 3.645%, B/C 2.97x

The 6-week bill is the shortest of the regular weekly tenors and sits in cash management territory, so demand here is driven less by rate views than by the ebb and flow of bill supply, quarter-end and tax-date cash needs, and the level of RRP balances that anchor the front of the curve. A bid-to-cover near 3x is within the normal range for this tenor, where cover ratios have historically run well above those of coupons precisely because the buyer base is deep and duration risk negligible; the more informative read is the high rate versus the when-issued level at the deadline, since tails and stop-throughs in bills, though small in absolute terms, are the established tell for whether supply is pressuring money market rates. Episodes of heavy bill issuance, typically around debt ceiling resolutions or deficit financing shifts, have tended to cheapen bills relative to OIS and lift repo, and the front-end complex usually absorbs that gradually rather than in a single auction. The follow-ons are the rest of the weekly bill calendar, dealer take-down shares across the auction block, and whether stop rates drift relative to RRP and SOFR fixings over coming weeks. As a single short-tenor result, this is routine supply information rather than a signal on policy.