According to WSJ, both UA and Delta have contacted the banks behind their respective co-branded credit cards, Chase and AMEX, in hopes of selling miles early. Normally, after a bank and an airline sign a co-branded credit card agreement, the bank regularly purchases miles from the airline to use for welcome bonuses. But UA and DL are already running short on cash flow and are planning to sell miles early to their co-branded card partners at a lower price. During the pandemic, AA, UA, and Delta all obtained large loans from banks and also pledged quite a few valuable assets as collateral. Now that most of those assets have more or less already been pledged, they have no choice but to start unloading future miles.
Selling off miles like this is actually pretty common too: airlines give up future profits in exchange for current cash flow. Back around 9/11, airlines did this as well.
If banks take in a huge batch of miles, we might even see a wave of record-high welcome bonuses to attract more customers. That said, it’s still too early to say that now. During the pandemic, travel and other spending have both shrunk, so it seems unlikely that issuers would immediately roll out record-high bonuses at a time like this. From the airlines’ perspective, if they dump a large batch of miles early and then follow up with a devaluation, that would be quite a move.
Right now, airlines are also running all kinds of record-high mileage sales. My suggestion is still not to throw your principal in just for a tiny bit of upside...