424B5 1 sprb-424b5-2026.htm 424B5 424B5

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-291152

PROSPECTUS SUPPLEMENT

(To Prospectus dated October 29, 2025)

Up to $75,000,000

Common Stock

We have entered into an Open Market Sale AgreementSM, dated March 9, 2026 (the “Sales Agreement”), with Jefferies LLC (“Jefferies”), relating to the sale of shares of our common stock offered by this prospectus supplement. In accordance with the terms of the Sales Agreement, under this prospectus supplement we may offer and sell shares of our common stock, $0.0001 par value per share, having an aggregate offering price of up to $75.0 million from time to time through Jefferies, acting as our agent.

Our common stock is listed on the Nasdaq Capital Market under the symbol “SPRB.” On March 6, 2026, the last reported sale price of our common stock on the Nasdaq Capital Market was $55.87 per share.

Sales of our common stock, if any, under this prospectus supplement may be made by any method deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on or through the Nasdaq Capital Market, the existing trading market for our common stock, or any other existing trading market for our common stock. Jefferies is not required to sell any specific number or dollar amount of securities, but will act as our sales agent using commercially reasonable efforts to sell on our behalf all of the shares of our common stock requested to be sold by us, consistent with its normal trading and sales practices, on mutually-agreed terms between Jefferies and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

Jefferies will be entitled to compensation at a commission rate of 3.0% of the gross proceeds of any shares of common stock sold under the Sales Agreement. In connection with the sale of the common stock on our behalf, Jefferies will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation paid to Jefferies will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Jefferies with respect to certain liabilities, including liabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”). See the section titled “Plan of Distribution” beginning on page S-11 of this prospectus supplement for additional information regarding the compensation to be paid to Jefferies.

We are a “smaller reporting company” under applicable Securities and Exchange Commission rules, and as such, have elected to comply with reduced public company reporting requirements for this prospectus supplement and the accompanying prospectus and the documents incorporated by reference herein and therein and may elect to comply with reduced public company reporting requirements in future filings.

Investing in our common stock involves a high degree of risk. You should read this prospectus supplement and the accompanying prospectus as well as the information incorporated herein and therein by reference carefully before you make your investment decision, including the risks and uncertainties described under the section titled “Risk Factors” beginning on page S-5 of this prospectus supplement and on page 6 of the accompanying prospectus and under similar headings in the other documents that are incorporated by reference into this prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

Jefferies

The date of this prospectus supplement is March 9, 2026.


Prospectus Supplement
	Page

ABOUT THIS PROSPECTUS SUPPLEMENT	S-1
PROSPECTUS SUPPLEMENT SUMMARY	S-2
RISK FACTORS	S-5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	S-7
USE OF PROCEEDS	S-8
DILUTION	S-9
PLAN OF DISTRIBUTION	S-11
LEGAL MATTERS	S-13
EXPERTS	S-13
WHERE YOU CAN FIND MORE INFORMATION	S-13
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	S-14


Prospectus
	Page

ABOUT THIS PROSPECTUS	1
PROSPECTUS SUMMARY	2
RISK FACTORS	6
SELECTED FINANCIAL DATA REFLECTING REVERSE STOCK SPLIT	7
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	9
USE OF PROCEEDS	10
DESCRIPTION OF CAPITAL STOCK	11
DESCRIPTION OF DEBT SECURITIES	15
DESCRIPTION OF WARRANTS	22
LEGAL OWNERSHIP OF SECURITIES	25
PLAN OF DISTRIBUTION	29
LEGAL MATTERS	32
EXPERTS	32
WHERE YOU CAN FIND MORE INFORMATION	32
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	32


Common stock offered by us		Shares of our common stock having an aggregate offering price of up to $75.0 million.
Common stock to be outstanding immediately following this offering		Up to 2,714,445 shares (as more fully described in the notes following this table), assuming sales of 1,342,402 shares of our common stock in this offering at an assumed offering price of $55.87 per share, which was the last reported sale price of our common stock on the Nasdaq Capital Market on March 6, 2026. The actual number of shares issued will vary depending on how many shares of our common stock we choose to sell and the prices at which such sales occur.
Plan of Distribution		“At the market offering” that may be made from time to time through the sales agent, Jefferies. See the section titled “Plan of Distribution” on page S-11 of this prospectus supplement for additional information.
Use of Proceeds		We currently intend to use the net proceeds from this offering, if any, to fund our clinical programs, and for general corporate purposes, including working capital, operating expenses and capital expenditures. See the section titled “Use of Proceeds” on page S-8 of this prospectus supplement for additional information.
Risk Factors		Investing in our common stock involves a high degree of risk. You should carefully consider the information set forth in the section of this prospectus supplement titled “Risk Factors” beginning on page S-5, as well as other information included in this prospectus supplement, the accompanying prospectus and the documents incorporated herein or therein by reference before deciding to invest in our common stock.
Nasdaq Capital Market Symbol		“SPRB”



Assumed public offering price per share			$	55.87
Historical net tangible book value per share as of December 31, 2025	$	30.99
Increase per share attributable to new investors		11.31

As adjusted net tangible book value per share after giving effect to this offering				42.30

Dilution in adjusted net tangible book value per share to new investors			$	13.57


	Year Ended December 31,
	2024			2023
Net loss	$	(53,036	)	$	(47,919	)
Net loss per share, basic and diluted	$	(1.29	)	$	(1.24	)
Weighted-average shares of common stock outstanding, basic and diluted		41,264,948			38,510,220
Shares of common stock outstanding at year end		42,231,285			41,029,832


	Three Months Ended March 31,
	2025			2024
Net loss	$	(14,041	)	$	(11,625	)
Net loss per share, basic and diluted	$	(0.32	)	$	(0.28	)
Weighted-average shares of common stock outstanding, basic and diluted		43,944,946			41,096,231
Shares of common stock outstanding at period end		42,231,285			41,154,799

ABOUT THIS PROSPECTUS SUPPLEMENT

PROSPECTUS SUPPLEMENT SUMMARY

Company Overview

Implications of Being a Smaller Reporting Company

Corporate Information

RISK FACTORS

Risks Related to This Offering

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

USE OF PROCEEDS

PLAN OF DISTRIBUTION

LEGAL MATTERS

EXPERTS

WHERE YOU CAN FIND MORE INFORMATION

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

This prospectus may not be used to consummate a sale of any securities unless accompanied by a prospectus supplement.

ABOUT THIS PROSPECTUS

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

PROSPECTUS SUMMARY

Company Overview

Implications of Being an Emerging Growth Company and Smaller Reporting Company

Corporate Information

The Securities We May Offer

This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

RISK FACTORS

SELECTED FINANCIAL DATA REFLECTING REVERSE STOCK SPLIT

Reverse Stock Split

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

USE OF PROCEEDS

DESCRIPTION OF CAPITAL STOCK

General

Common Stock

Preferred Stock

Anti-Takeover Provisions

Choice of Forum

Exchange Listing

Transfer Agent and Registrar

DESCRIPTION OF WARRANTS

General

Exercise of Warrants

Governing Law

Enforceability of Rights by Holders of Warrants

LEGAL OWNERSHIP OF SECURITIES

Book-Entry Holders

Street Name Holders

Legal Holders

Special Considerations for Indirect Holders

Global Securities

Special Considerations for Global Securities

Special Situations When a Global Security Will Be Terminated

PLAN OF DISTRIBUTION

LEGAL MATTERS

EXPERTS

WHERE YOU CAN FIND MORE INFORMATION

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

SEC Form 424B5 filed by Spruce Biosciences Inc.