Agius, chairman at Barclays for five-and-a-half years, will stay in his position until a succession plan is assured.
Here is what the scandal is all about:
1. UK bank Barclays had last week said that it will pay $453 million to US and British authorities to settle allegations that it manipulated key interest rates, increasing pressure on other banks to cooperate in a probe that could cost the financial industry billions of dollars.
2. US regulators have been investigating allegations that several banks, including Barclays, manipulated the London Interbank Lending Rate (Libor), which underpins trillions of dollars of derivatives contracts worldwide and is also widely used as a reference rate for corporate lending. Libor underlies everything from derivatives trades to US consumer credit card rates to loans as far afield as those financing Turkish phone networks. Barclays also tried to manipulate Euribor, a separately managed series of euro-denominated rates.
3. The US Commodity Futures Trading Commission (CFTC) said Barclays attempted to manipulated Libor submissions "sometimes on a daily basis" over a four-year period starting in 2005. The CFTC ordered the bank to pay a $200 million penalty, saying it was the largest civil monetary penalty it has ever imposed.
4. Investigators were helped by the extensive email traffic among Barclays employees involved. In one email, after a Barclays swaps trader asked for low levels to be reported on certain short-term rates, an employee who submitted rates for the survey responded by email, "Done ... for you big boy ..."
"Dude, I owe you big time! Come over one day after work and I'm opening a bottle of Bollinger," a trader from another firm emailed a banker at Barclays, showing his thanks for the rate set artificially low.
5. A key conversation held in October 2008 that was last week highlighted in documents about the scandal was between Bank of England (BoE) deputy governor Paul Tucker and Barclays CEO Bob Diamond, people familiar with the matter said. As the credit crisis took hold in 2008, allegations started mounting that Libor no longer reflected banks' real borrowing costs, and authorities began examining whether traders tried to influence whether the rate went up or down to profit on bets on its future direction.
With inputs from Reuters