Company: CIFRW
Filing Date: 2025-05-22
Form Type: 424B5
Source: 0001193125-25-124285
Chunk: 11

Company: Cipher Mining Inc.
Filing Date: 2025-05-22
Form: 424B5
Chunk 11
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hang by
prepaying these obligations.

S-2

The Offering The summary below describes the principal terms of the notes. Certain of the terms of the notes described below are subject to important limitations and exceptions that are described in more detail under the caption “Description of Notes.” As used in this section, “we,” “our” and “us” refer to Cipher Mining Inc. and not to its subsidiaries.

| Issuer | Cipher Mining Inc., a Delaware corporation. |

| Notes | $150,000,000 aggregate principal amount of 1.75% convertible senior notes due 2030. We have granted the underwriters an option, which is exercisable within 30 days after the date of this prospectus supplement, to purchase up to an additional 
 $22,500,000 aggregate principal amount of notes solely to cover over-allotments.                                                                                                                                                                  |

| Ranking | The notes will be our senior, unsecured obligations and will be: |

| • |     | equal in right of payment with our existing and future senior, unsecured indebtedness; |

| • |     | senior in right of payment to our existing and future indebtedness that is expressly subordinated to the notes; |

| • |     | effectively subordinated to our existing and future secured indebtedness, to the extent of the value of the 
 collateral securing that indebtedness; and                                                                  |

| • |     | structurally subordinated to all existing and future indebtedness and other liabilities, including trade 
 payables, and (to the extent we are not a holder thereof) preferred equity, if any, of our subsidiaries. |

| Conversion Rights | Noteholders may convert their notes at their option only in the following circumstances: |

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| • |     | during the five consecutive business days immediately after any 10 consecutive trading day period (such 10                                                                                                                                    
 consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per 
 share of our common stock on such trading day and the conversion rate on such trading day;                                                                                                                                                    |

| • |     | upon the occurrence of certain corporate events or distributions on our common stock, as described in this 
 prospectus supplement;                                                                                     |

| • |     | if we call such notes for redemption; and |

| We will settle conversions by paying or delivering, as applicable, cash, shares