The document discusses the ACCRINT Excel function which calculates accrued interest for a security paying periodic interest. It lists the function arguments including issue date, first interest date, settlement date, rate, par value, payment frequency, and optional basis and calculation method arguments. An example calculation is provided for a security issued January 1, 2018 with first interest on April 1, 2018, settling on December 31, 2019 with an 8% annual coupon paid quarterly on a 30/360 basis.