That's not really what has happened here. Asset/fund managers buy all types of fixed income instruments - government bills, notes, bonds, municipals debt, corp

That's not really what has happened here. Asset/fund managers buy all types of fixed income instruments - government bills, notes, bonds, municipals debt, corporate debt, mortgages, bank loans, on and on. During the mayhem in late Feb/early March the secondary market for any and all of that debt for all intents vanished. This left many funds in difficult positions - their cash reserves are low and not sufficient to meet large daily redemptions therefore they need to sell assets they own. Those that also owned equities/commodities (balanced style funds) sold those more liquid assets, adding fuel to that dumpster fire. However, debt only funds were still left with no where to go. Thus the Fed stepped in and agreed to purchase exceedingly large amounts of debt instruments - pretty much anything rated investment grade. Thus the Fed monetized those holdings and we are now seeing that cash pushing up equity prices. The above is a little bit over simplified and leaves out many other players (ie repo problems) Also - the Treasury issues debt every week to meet the regular financial obligations of the US government, not just for special needs (various bailouts)