ECB ended the stigma of borrowing by making its cash auction buy-all at a fixed price

In late 2008, after Lehman failed, euro-area banks stopped lending to each other because nobody could tell which bank was solvent, and the interbank money market froze.

The ECB's usual weekly tender made it worse. It fixed a quantity of cash and asked banks to bid an interest rate; the most aggressive, most desperate bidders got filled first, so the size of your bid told the market how weak your bank was. The weaker the bank, the more it needed the cash, and the more its own bid exposed it.

The ECB flipped the mechanism. From the weekly operation settled on 15 October 2008 it ran a fixed-rate tender with full allotment: one posted rate, and every eligible bank got all the cash it asked for against collateral. The amount each bank took became private, and the rate stopped carrying information about who the weak borrower was.

It also cut the corridor around the policy rate and kept the anchor, so the money market repriced around the ECB's posted rate rather than around a signal of desperation. The procedure stayed in place through 2020.