A type of investment vehicle that provides a specified monthly payment to the investor. This monthly payment is intended to be a stable form of income and is therefore typically suited for retired persons or senior citizens without other substantial sources of monthly income. A monthly income plan can be thought of as a budget for a retirement income. Rather than reaching retirement and spending your nest egg by making random withdrawals of varying amounts, a monthly income plan can ensure you receive a stable amount of funds each month to spend, which limits the risk of over-spending. In this regard, an MIP is similar in many ways to an annuity.