BNY Mellon replaces MUFG as administrator for GBAB (GBAB)

Rhea-AI Filing Summary

Guggenheim Taxable Municipal Bond & Investment Grade Debt Trust replaced its administrator and fund accounting agent. On December 15, 2025, The Bank of New York Mellon (BNY) succeeded MUFG Investor Services (US) LLC under a Fund Accounting and Administration Agreement. BNY will perform administrative, bookkeeping, accounting and pricing functions and will be paid a fee accrued daily and paid monthly based on average daily net assets, subject to an annual minimum; the Trust will also reimburse certain out-of-pocket expenses.

Filed Pursuant to Rule 424(b)(3)

Securities Act File No. 333-267848

Investment Company Act File No. 811-22437

SUPPLEMENT

(To the Prospectus and Prospectus Supplement, each dated April 12, 2023)

Supplement Dated December 15, 2025

to the currently effective Prospectus and Prospectus Supplement, each as may be further supplemented from time to time, for Guggenheim Taxable Municipal Bond & Investment Grade Debt Trust (the “Trust”)

This supplement provides updated information beyond that contained in the Prospectus and Prospectus Supplement and should be read in conjunction with the foregoing documents.

On December 15, 2025, The Bank of New York Mellon (“BNY”) replaced MUFG Investor Services (US) LLC (“MUFG”) as administrator and fund accounting agent to the Trust.

Pursuant to a Fund Accounting and Administration Agreement with the Trust, as may be amended and/or restated from time to time, BNY performs administrative functions and bookkeeping, accounting and pricing functions for the Trust. For these services, BNY receives a fee, accrued daily and paid monthly, based on average daily net assets of the Trust, subject to a minimum fee per year. The Trust also reimburses BNY for certain out-of-pocket expenses.

In view of the foregoing, references to MUFG as administrator and fund accounting agent to the Trust are hereby replaced with BNY as the context requires.

Please Retain This Supplement for Future Reference

SUPP-PRO-GBABx1225

SUPPLEMENT

(TO THE STATEMENT OF ADDITIONAL INFORMATION DATED APRIL 12, 2023)

Supplement Dated December 15, 2025

to the currently effective Statement of Additional Information, as may be supplemented from time to time, (the “SAI”) for Guggenheim Taxable Municipal Bond & Investment Grade Debt Trust (the “Trust”)

This supplement provides updated information beyond that contained in the SAI and should be read in conjunction with the SAI.

On December 15, 2025, The Bank of New York Mellon (“BNY”) replaced MUFG Investor Services (US) LLC (“MUFG”) as administrator and fund accounting agent to the Trust.

Pursuant to a Fund Accounting and Administration Agreement with the Trust, as may be amended and/or restated from time to time, BNY performs administrative functions and bookkeeping, accounting and pricing functions for the Trust. For these services, BNY receives a fee, accrued daily and paid monthly, based on average daily net assets of the Trust, subject to a minimum fee per year. The Trust also reimburses BNY for certain out-of-pocket expenses.

In view of the foregoing, references to MUFG as administrator and fund accounting agent to the Trust are hereby replaced with BNY as the context requires.

Please Retain This Supplement for Future Reference

SUPP-SAI-GBABx1225

FAQ

What change did GBAB disclose in this supplement?

The Trust replaced its administrator and fund accounting agent on December 15, 2025. The Bank of New York Mellon succeeded MUFG to perform administration, bookkeeping, accounting and pricing functions under a Fund Accounting and Administration Agreement.

When did the administrator change for GBAB take effect?

The change took effect on December 15, 2025. The supplement dated December 15, 2025 updates the Prospectus, Prospectus Supplement and Statement of Additional Information to reflect BNY as administrator and fund accounting agent.

How will BNY be compensated for services to GBAB?

BNY will receive a fee accrued daily and paid monthly, calculated based on the Trust's average daily net assets and subject to a minimum annual fee. The Trust will also reimburse BNY for certain out-of-pocket expenses.

Does the supplement change the Trust’s investment strategy or fees charged to investors?

The supplement updates the administrator and accounting agent only. It states BNY will perform administrative and accounting functions and be paid fees as described; it does not state any changes to investment strategy or investor-level fee schedules.

Which documents does this supplement update for GBAB?

The supplement updates the Prospectus, Prospectus Supplement, and Statement of Additional Information dated April 12, 2023. The December 15, 2025 supplement replaces references to MUFG with BNY where applicable.