BACKGROUND
Bankers ensure that any un-needed
surplus would be deposited by the dealers towards the end of a trading day.
They would place this money on overnight deposits with other banks. The
benchmark for interest payment on this deposit would be the Libor (or Euribor).
Settlement
rate was not determined by what rates were actually in the market. Instead, the
British Banker’s Association (BBA) polled banks, asking them what the rates were. The
highest and lowest quoted rates were discarded and the rest were averaged,
giving the settlement rate.
The Libor was also used as an "weather report" of what conditions were in the market that day and a rough indicative of the banks' financial condition.