M2 was M1 plus commercial bank savings and small time deposits, and M3 was M2 plus deposits at mutual savings banks, savings and loans, and credit unions; data from the latter type of institution were available only monthly. M4 was M2 plus large time deposits, and M5 was M3 plus large time deposits.
Changes in definitions make it difficult to track the historical development of the various monetary aggregates. Approximately, the 2006 definition of M1 is equivalent to this older definition, the 2006 definition of M2 is equivalent to the older definition of M3, and the definition of M3 at its date of last publication was equivalent to the older definition of M5.