I've heard of overnight lending but forgot why it matters
rates for overnight bank to Bank lending went up 106x from March 2022 to March 2023
https://fred.stlouisfed.org/series/SOFR
this rate is backed by treasury bill lending
in a lot of ways this wrecked the economy
a lot of ways zero interest rates wrecked the economy also
Discussion
it lubricates the financial system so a bank doesn't have to wait to fulfill withdrawal requests in such things as that
I met someone who's job it was to keep a excel spreadsheet at a bank of how much they had borrowed or lent to other banks at the end of the day. He used VBA to automate some of the stuff :-D which I'm sure makes the computer programmers wince.
Something like "citi owed Wells Fargo x million" at the end of the day.