IOU

Should a player lose beyond his ability to pay, the others may allow him time to pay off his loss—usually, time until the next game—and he may offer up an IOU.

If it doesn't, the EU could forgive Kyiv's debt – but it would still have to repay the money it borrowed to fund the IOU to Euroclear.

Governments sell bonds - essentially an IOU - to raise money for public spending and in return they pay interest.

The government sell bonds - essentially an IOU - to raise money from financial markets and these are viewed as a safe investment, meaning the US normally does not need to offer high rates to attract buyers.

Investors see US Treasury securities as one of the safest possible bets, because the bonds - which are kind of like an IOU - are backed by the US government.