If that's true, it's the repo rate, at one-week maturities.

If it's been overnight lending at the punitive "marginal lending facility" rate, it's 1.75%, when the overnight interbank lending rate is not much higher than 0.25%

All of this lending is overcollateralised, as it is "against eligible assets" at a discount set by the ECB itself at its discretion.

Anyway you look at it, the ECB is making a lot of money on this lending. It's called Seigniorage.

Keynesianism is intellectually hard, as evidenced by the inability of many trained economists to get it - Paul Krugman