An annuity is a long-term investment between you, the annuitant, and an insurance company, the annuity issuer. Under this contract, you pay after-tax funds to the annuity issuer, who then invests your principal to meet your financial objectives and pays you or your beneficiary back with earnings (subject to the claims-paying ability of the issuer).
If you have a fixed annuity, your interest rate is guaranteed. With a variable annuity, your earnings are linked with the fluctuating performance of your investments and may be worth more or less than your principal when redeemed. In addition, you have added control in how your money is invested, creating a higher potential for growth. However, this option comes with a higher risk in return.
Unlike other investment plans, there is no limit to how much you can invest in an annuity. Your funds will steadily grow with a tax-deferred status, and you pay your regular tax income rate on only your earnings upon withdrawal.