[424B5] BioXcel Therapeutics, Inc. Prospectus Supplement (Debt Securities)

Rhea-AI Filing Summary

BioXcel Therapeutics (Nasdaq: BTAI) has filed a prospectus supplement (Form 424B5) to amend its April 3 ATM program with Canaccord Genuity. Having already sold the full $8.135 million originally registered, the company is now registering up to $3.5 million in additional common stock to remain within Form S-3, Instruction I.B.6 limits that cap primary offerings at one-third of public float when that float is below $75 million.

As of 6 Aug 2025, BTAI’s public float is $35.9 million (12.1 million non-affiliate shares × $2.97 close). Under the rule, it may currently issue up to $3.83 million; this filing covers most of that capacity. Should the float rise above $75 million, the restriction disappears; a lower float would further constrain issuance. Shares will be sold from time to time through Canaccord at prevailing market prices, generating discretionary working capital. The filing does not change business strategy, risk factors or financial results but does signal potential dilution and dependence on external capital.

Positive

• Maintains capital-raising flexibility by adjusting ATM capacity within SEC limits.
• Potential liquidity boost of up to $3.5 million without underwriting fees typical of larger offerings.

Negative

• Dilution risk: additional share issuance will incrementally increase outstanding shares.
• Signals reliance on external financing rather than operating cash flows.

Insights

Securities Analyst

TL;DR: Small ATM top-up adds liquidity but continues dilution trend; neutral impact.

The $3.5 million registration equals roughly 10% of the 12-month public-float capacity and less than 2% of market cap, so balance-sheet benefit is modest. Nevertheless, serial ATM use highlights ongoing cash burn and reliance on equity markets ahead of key clinical catalysts. Given that the prior $8.1 million has already been issued, investors should expect continued share count creep, though at a limited dollar size. Impact on valuation is neutral to slightly negative because proceeds shore up liquidity without addressing core profitability.

Corporate Finance Specialist

TL;DR: Filing keeps ATM compliant with S-3 rules; administrative, low impact.

This amendment is primarily procedural—adjusting the ceiling to match the current one-third float allowance. The company prudently preserves capital-raising flexibility while avoiding regulatory overstep. Because pricing is at-the-market, execution risk is minimal, but proceeds depend on trading volume and price. Dilution risk exists yet remains manageable at today’s float size. Overall, the action maintains optionality rather than signaling a major strategic shift.

As Filed Pursuant to Rule 424(b)(5)
Registration No. 333-275261

PROSPECTUS SUPPLEMENT

(To Prospectus Supplement April 3, 2025

and Prospectus dated November 13, 2023)

Up to $3,500,000

Common Stock

This Prospectus Supplement supplements the prospectus supplement April 3, 2025 (the “ATM Prospectus Supplement”), relating to the offer and sale of shares of our common stock, $0.001 par value per share, having an aggregate offering price of up to $8,135,000 pursuant to the terms of an equity distribution agreement (the “Equity Distribution Agreement”) with Canaccord Genuity LLC (“Canaccord”). Through the date hereof, we have sold an aggregate of $8,135,000 of shares of our common stock through Canaccord under the Equity Distribution Agreement. This Prospectus Supplement should be read in conjunction with the ATM Prospectus Supplement, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the ATM Prospectus Supplement. This Prospectus Supplement is not complete without, and may only be delivered or utilized in connection with, the ATM Prospectus Supplement, and any future amendments or supplements thereto.

On March 28, 2025, the date we filed our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, we became subject to the offering limits in General Instruction I.B.6 of Form S-3. As of the date of this Prospectus Supplement, the aggregate market value of our common stock held by non-affiliates pursuant to General Instruction I.B.6 of Form S-3 is $35,893,213, which was calculated based on 12,085,257 shares of our outstanding common stock held by non-affiliates and a price of $2.97 per share, the closing price of our common stock on August 5, 2025. As of the date of this Prospectus Supplement, we have sold $8,135,000 of securities pursuant to General Instruction I.B.6 of Form S-3 during the 12 calendar months prior to, and including, the date of this Prospectus Supplement. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities in public primary offerings on Form S-3 with a value exceeding one-third of our public float (as defined by General Instruction I.B.6) in any 12 calendar month period so long as our public float remains below $75.0 million.

We are filing this Prospectus Supplement to amend the ATM Prospectus Supplement to increase the maximum amount of shares that we are eligible to sell pursuant to the Equity Distribution Agreement under General Instruction I.B.6. As a result of these limitations, we may currently offer and sell shares of our common stock having an aggregate offering price of up to $3,829,404 pursuant to the Equity Distribution Agreement. Pursuant to this Prospectus Supplement, we are registering the offer and sale of up to $3,500,000 of shares of our common stock. However, in the event that our public float increases or decreases, we may sell securities in public primary offerings on Form S-3 with a value up to one-third of our public float, in each case calculated pursuant to General Instruction I.B.6 and subject to the terms of the Equity Distribution Agreement. In the event that our public float increases above $75.0 million, we will no longer be subject to the limits in General Instruction I.B.6 of Form S-3.

Our common stock trades on the Nasdaq Global Market under the symbol “BTAI.” On August 5, 2025, the last reported sale price of our common stock on the Nasdaq Global Market was $2.97 per share.

INVESTING IN OUR COMMON STOCK INVOLVES RISKS. SEE THE “RISK FACTORS” ON PAGE S-8 OF THE ATM PROSPECTUS SUPPLEMENT AND IN THE DOCUMENTS INCORPORATED BY REFERENCE IN THE REGISTRATION STATEMENT CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR COMMON STOCK.

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

Canaccord Genuity

The date of this prospectus supplement is August 6, 2025.

FAQ

How much additional capital can BTAI raise under this prospectus supplement?

The filing registers up to $3.5 million of common stock.

Why is BioXcel subject to Form S-3 Instruction I.B.6 limits?

Its public float is $35.9 million, below the $75 million threshold that triggers the one-third-of-float cap.

What is the current public float and share price used for the calculation?

12,085,257 non-affiliate shares × $2.97 (close 5 Aug 2025) = $35.893 million float.

Will the limit change if BTAI's market cap rises?

Yes. If public float exceeds $75 million, the one-third cap no longer applies, allowing larger offerings.

Where will the shares be sold?

Through Canaccord Genuity under the existing Equity Distribution Agreement at prevailing Nasdaq prices.