Fidelity Investments on Wednesday announced the launch of four Fidelity Defined Maturity Funds, a series of four actively managed municipal income funds. The funds seek to bridge the gap between individual bonds and bond funds and, therefore, fill a gap in municipal bond investing, Fidelity said.

The funds also have defined end dates and will invest primarily in investment-grade municipal bonds, seeking a high level of current income as well as the preservation of capital.

To protect existing shareholders and ensure orderly liquidation of the funds, the Defined Maturity Funds will close to purchases for new and existing investors approximately 12 months prior to their maturity end dates.

“When compared to a traditional bond fund, the price volatility of the Defined Maturity Funds is designed to decline as their underlying bonds approach their maturity,” said Mark Sommer, co-manager of the funds. “However, unlike individual bonds, these funds do not return a pre-determined amount at the funds’ defined end dates. These funds may be appropriate for income-seeking investors who are interested in combining the defined-maturity feature of individual bonds with the many features of bond funds, including diversification and professional management, thus removing much of the legwork of individual bond investing.”

The Fidelity Municipal Income Funds have maturity dates ending in 2015, 2017, 2019 and 2021.

Investors can opt either to receive the income as monthly payments or to reinvest the money.