Fixed or Determinable Annual or Periodical Income (FDAP)
All income except (i) gains derived from the sale of real or personal property (including market discount and option premiums, but not including original issue discount) and (ii) items of income excluded from gross income, without regard to the US or foreign status of the owner of the income, such as tax-exempt municipal bond interest; income is fixed when it is paid in amounts know ahead of time; income is determinable whenever there is a basis for figuring the amount to be paid; income can be periodic if it is paid from time to time; income can be determinable or periodic, even if the length of time during which the payments are made is increased or decreased.