par: A number value representing the par (face) or maturity value of the security. par is commonly a number like 100, 1,000, or 1,000,000. par is often formatted as currency. If par is omitted (comma, but no value), par is assumed to be 1000.
days-basis: An optional European method for dates falling on the 31st of a month.
The currency shown in this function result depends on your Language & Region settings (in System Preferences in macOS 12 and earlier, System Settings in macOS 13 and later, and Settings in iOS and iPadOS).
Example
Suppose you are considering the purchase of a hypothetical security. The security was issued December 14, 2007 (issue), will settle May 1, 2009 (settle), has a face value of $1000 (par), and pays interest at an annual rate of 10% (annual-rate) calculated based on a 30/360 days basis (days-basis) only at maturity.
=ACCRINTM("12/14/2007", "05/01/2009", 0.10, 1000, 0) returns approximately 138.055555555556, which represents the interest accrued between the issue date and the settlement date. This amount would be added to the agreed price to determine the amount due to the seller by the purchaser of the security.