A premium income recognition methodology where premiums are assumed to be earned over the life of the policy. This method is used when data limitations mean that more accurate methods cannot be used. Under the 24ths basis all premiums written in a month (policies covering a 12 month period) are earned over 13 months. 1/24th of the premium is earned in the first month, 2/24ths in each subsequent month and 1/24th in the 13th month. The 24ths basis is commonly used where an insurer receives premiums via a monthly bordereaux.