Company: SRV
Filing Date: 2025-11-17
Form Type: 424B2
Source: 0001398344-25-021029
Chunk: 1

Company: NXG Cushing Midstream Energy Fund
Filing Date: 2025-11-17
Form: 424B2
Chunk 1
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 the Expiration Date. The Fund will pay a sales load on the Subscription Price. The Offer will expire at 5:00 p.m.,
Eastern time, on December 11, 2025, unless extended as described in this Prospectus Supplement (the “Expiration Date”).

Rights holders will not know the Subscription Price
at the time of exercise and will be required initially to pay for both the Common Shares subscribed for pursuant to the primary subscription
and, if eligible, any additional Common Shares subscribed for pursuant to the over-subscription privilege at the estimated Subscription
Price of $40.24 per Common Share and, except in limited circumstances, will not be able to rescind their subscription.

Exercising your Rights and investing in the Fund’s Common Shares involves a high degree of risk. See “Risks” on page 13 of the accompanying Prospectus.

The Offer will dilute the ownership interest and voting power of the Common Shares owned by Common Shareholders who do not fully exercise their Rights. Common Shareholders who do not fully exercise their Rights should expect, upon completion of the Offer, to own a smaller proportional interest in the Fund than before the Offer. Further, if the net proceeds per Common Share from the Offer are at a discount to the Fund’s NAV per Common Share, this Offer will reduce the Fund’s NAV per Common Share.

Neither the Securities and Exchange Commission (“SEC”) nor any state securities commission has approved or disapproved of these securities or determined if this Prospectus Supplement or the accompanying Prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

(continued on following page)

|                                           | Per Share |    Total(1) |
| Estimated Subscription Price(2)           |    $40.24 | $62,605,395 |
| Estimated Sales Load(2)(3)                |     $1.41 |  $2,191,189 |
| Proceeds, before expenses, to the Fund(4) |    $38.83 | $60,414,206 |

(notes on following page)

The Common Shares are expected
to be delivered on or about December 18, 2025, unless the Offer is extended.

<div align='center'>UBS Investment Bank

This Prospectus Supplement is dated November 17, 2025.</div>

| ii |

(Motes from previous page)

| (1) | Assumes that all Rights are exercised at the estimated Subscription Price. All of the Rights may not be exercised. |

| (2)