Template:Csa Interest Period summ
Sometimes known as a “calculation period”, a more general term that can refer to other, non-interest-related determinations, an “interest period” is the space in time between interest payments on an interest-bearing financial instrument. Common ones: annual and semi-annual (especially for fixed rate products, since QED the interest rate doesn’t periodically change so there’s no particular market risk consequence for paying interest more frequently and operationally it is a hassle). Now there is a credit risk consequence, credit being a function of duration, but it is, all told, at the short end and it relates to interest and not principal.
Anyhow: fixed rates tend to pay annually, semi-annually or quarterly and floating rates, being path-dependent and more susceptible to intra-period volatility, are more commonly, monthly, weekly or daily.
Common amendments
You may see some fastidious operations teams asking to modify this to be a calendar month thing. You have to wonder why.