Supplement to the

Fidelity® Total Bond K6 Fund

October 30, 2023

STATEMENT OF ADDITIONAL INFORMATION

Effective March 1, 2024, the fund's sub-advisory agreements with FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited, and Fidelity Management & Research (Japan) Limited were amended. The following information supplements similar information found in the "Management Contract" section.

Under the terms of the sub-advisory agreements, FMR pays each sub-adviser monthly fees equal to 110% of the sub-adviser's costs for providing sub-advisory services.

TBDK6-SSTK-0424-102-1.9899407.102 April 2, 2024

Supplement to the

Fidelity® Series Government Bond Index Fund

October 30, 2023

STATEMENT OF ADDITIONAL INFORMATION

Effective March 1, 2024, the fund's sub-advisory agreements with FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited, and Fidelity Management & Research (Japan) Limited were amended. The following information supplements similar information found in the "Management Contract" section.

Under the terms of the sub-advisory agreements, FMR pays each sub-adviser monthly fees equal to 110% of the sub-adviser's costs for providing sub-advisory services.

XGB-SSTK-0424-102-1.9899788.102 April 2, 2024