Company: RFMZ
Filing Date: 2025-05-21
Form Type: 424B5
Source: 0001398344-25-009954
Chunk: 21

Company: RiverNorth Flexible Municipal Income Fund II, Inc.
Filing Date: 2025-05-21
Form: 424B5
Chunk 21
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 by referring you to those documents. The information incorporated by reference is an important part of this Prospectus, and later information that the Fund files with the SEC will automatically update and supersede this information.

The documents listed below, and any reports and other documents subsequently filed with the SEC pursuant to Rule 30(b)(2) under the 1940 Act and Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), prior to the termination of the offering, are incorporated by reference into this Prospectus Supplement and deemed to be part of this Prospectus Supplement from the date of the filing of such reports and documents:

| ● | the Fund’s description of common stock contained in its Registration                                                                       
 Statement on Form 8-A (File No. 811-23586), as filed with the SEC on July 9, 2020, including any amendment or report filed for the purpose 
 of updating such description prior to the termination of the offering.                                                                     |

| S-10 |

<div align='center'>ADDITIONAL INFORMATION</div>

The Fund is subject to the informational
requirements of the Exchange Act and the 1940 Act and in accordance therewith files reports and other information with the Securities
and Exchange Commission (“SEC”). The SEC maintains a web site at sec.gov containing reports, proxy and information statements
and other information regarding registrants, including the Fund, that file electronically with the SEC.

This Prospectus Supplement and
accompanying Prospectus constitutes part of a Registration Statement filed by the Fund with the SEC under the Securities Act and the 1940
Act. This Prospectus Supplement and accompanying Prospectus omits certain of the information contained in the Registration Statement,
and reference is hereby made to the Registration Statement and related exhibits for further information with respect to the Fund and the
Common Shares offered hereby. Any statements contained herein concerning the provisions of any document are not necessarily complete,
and, in each instance, reference is made to the copy of such document filed as an exhibit to the Registration Statement or otherwise filed
with the SEC. Each such statement is qualified in its entirety by such reference. The complete Registration Statement may be obtained
from the SEC upon payment of the fee prescribed by its rules and regulations or free of charge through the SEC’s website (sec.gov).

| S-11 |

BASE PROSPECTUS

<div align='center'>$400,000,000

RiverNorth Flexible Municipal Income Fund II