13th month refers to compensation equivalent to either one-twelfth or one month’s base salary. The practice originated in the Philippines in 1975 by President Ferdinand Marcos with Presidential Decree No. 851. The annual bonus is typically paid in December before the Christmas holidays, although organizations may elect to pay in installments.
Many countries have informal or legal mandates for the 13th-month payment, including most nations in Central and South American, as well as many countries throughout Asia.