Company: SRV
Filing Date: 2025-10-22
Form Type: N-2/A
Source: 0001398344-25-019582
Chunk: 50

Company: NXG Cushing Midstream Energy Fund
Filing Date: 2025-10-22
Form: N-2/A
Chunk 50
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-dealer, bank or trust company, the privacy
policy of your financial intermediary would govern how your nonpublic personal information would be shared with nonaffiliated third parties.

<div align='center'>30

$500,000,000

NXG Cushing® Midstream Energy Fund

Common Shares

Subscription Rights for Common Shares

31

The information in this Statement of Additional
Information is not complete and may be changed. The Fund may not sell these securities until the registration statement filed with the
Securities and Exchange Commission is effective. This Statement of Additional Information is not an offer to sell these securities and
is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to Completion, dated October 22, 2025

$500,000,000

NXG Cushing Midstream
Energy Fund

Common Shares
Subscription Rights for Common Shares

Statement of Additional Information</div>

NXG Cushing
Midstream Energy Fund (the “Fund”) was formed as a Delaware statutory trust on May 23, 2007 and is a non-diversified,
closed-end management investment company. The Fund’s investment objective is to obtain a high after-tax total return from a combination
of capital appreciation and current income. No assurance can be given that the Fund’s investment objective will be achieved.

This Statement of Additional
Information (“SAI”) is not a prospectus, but should be read in conjunction with the prospectus for the Fund dated , 2025
(the “Prospectus”). Investors should obtain and read the Prospectus prior to purchasing common shares. A copy of the Prospectus
may be obtained, without charge, by calling the Fund at (214) 692-6334.

The Prospectus and this SAI
omit certain of the information contained in the registration statement filed with the Securities and Exchange Commission (“SEC”).
The registration statement may be obtained from the Securities and Exchange Commission upon payment of the fee prescribed, or inspected
at the Securities and Exchange Commission’s office or via its website (www.sec.gov) at no charge. Capitalized terms used
but not defined herein have the meanings ascribed to them in the Prospectus.

The Fund is managed by Cushing
Asset Management, LP d/b/a NXG Investment Management (the “Investment Adviser”).

<div align='center'>This Statement of Additional Information is
dated , 2025.

TABLE OF CONTENTS</div>

| THE FUND                               | S-