Curium agreed to buy Lantheus. What the months before close decide for the people who built it.

• Announced August 3, 2026 by Curium and Lantheus. The merger agreement is dated August 3, 2026, among Lantheus, Curium US Holdings LLC and Coco Merger Sub Inc., and Lantheus’s board approved the deal unanimously. The August 3, 2026 release describes Curium as a radiopharmaceutical company whose controlling shareholder is the investment firm CapVest Partners LLP.
• Consideration is $102.50 in cash for each Lantheus share, without interest, plus one contingent value right, a CVR, for each share (Section 2.1(a)). The companies stated a total per share consideration of up to $114.50 and a total transaction value of up to approximately $8.0 billion. The release says there can be no assurance that any payments will be made on the CVRs. Each CVR pays up to $12.00 more in cash if set sales milestones for Lantheus products are reached through 2030, and may pay nothing.
• The CVR agreement sets eight milestones, each paid once, measured on adjusted sales as that agreement defines them. Adjusted sales count product sales in the U.S. and Canada in full and, with some exceptions, sales elsewhere at 20%, so they are not the same as reported revenue. For prostate cancer diagnostics, including PYLARIFY, adjusted sales in calendar year 2030 of at least $950 million pay $1.00 per CVR, at least $1.1 billion another $1.00, and at least $1.2 billion, $1.5 billion and $1.75 billion $2.00 each. For neurology diagnostics, including Neuraceq, at least $300 million in any one of 2028, 2029 or 2030 pays $2.00, and at least $350 million another $1.00. For DEFINITY, at least $400 million in 2030 pays $1.00. A milestone not reached before January 1, 2031 pays nothing.
• Curium must fund a payment on the prostate and DEFINITY milestones by the earlier of 45 days after the audit report for 2030 or March 31, 2031, and on a neurology milestone by the earlier of 45 days after the audit report for the milestone year or March 31 of the next year. The rights agent then has ten business days to pay holders. The CVRs pay no interest, carry no voting rights, and cannot be sold or transferred except in limited cases such as death or a court order. Curium agreed to use good faith and commercially reasonable efforts, as the CVR agreement defines them, for the approved products, but is not required to put any level of effort or resources into developing a product or running clinical trials. The merger agreement calls for the CVR agreement to be signed substantially in the form attached to it.
• At announcement, the companies said the deal was expected to close in the first half of 2027. In its quarterly report dated November 5, 2026, Lantheus said it and Curium continued to expect to complete the merger in the first half of 2027, subject to the end of the Hart-Scott-Rodino Act waiting period and the other closing conditions. Lantheus said its stock would no longer be publicly traded on Nasdaq or any other public market after the merger.
• Lantheus stockholders adopted the merger agreement at a virtual special meeting on October 14, 2026, with 55,457,863 shares voted for, 1,563,807 against and 162,833 abstaining, out of 65,299,875 shares outstanding on the September 1, 2026 record date.
• Both companies filed under the Hart-Scott-Rodino Act on August 18, 2026. Curium withdrew its filing on September 17, 2026 to give the FTC more time to review the deal, and refiled on September 21, 2026, which started a new 30 day waiting period. On October 21, 2026, each company received a Second Request from the FTC for more information, which extends the waiting period until 30 days after both have substantially complied, unless the FTC ends it sooner.
• The proxy says closing also needs approval from the German Federal Cartel Office and from the Swedish Inspectorate for Strategic Products under Sweden’s foreign direct investment law. It says the companies agreed to send a voluntary briefing paper to the UK Competition and Markets Authority, whose approval becomes a closing condition if the CMA opens an investigation, asks for a merger notice, or does not confirm it has no further questions. The proxy also says radiation and nuclear licenses held in New Jersey and Massachusetts need filings and approvals before closing, and that other regulatory approvals may become conditions to the merger.
• If the merger has not closed by the end of the day Eastern Time on May 2, 2027, a Sunday, the agreement can be terminated. That date moves later if a government shutdown keeps the companies from making an HSR Act filing, and once by up to three months if every condition but the antitrust and foreign investment approvals has been met and, if Lantheus asked for one after an FTC staff recommendation, Curium made a regulatory commitment in writing, but never beyond November 30, 2027 (Section 8.1(d)). Closing takes place no later than the fifth business day after the last condition is met or waived, unless Lantheus and Curium agree on another date (Section 1.2).
• Every unvested option vests in full right before close (Section 2.4(a)). Options priced under $102.50 are cancelled for cash equal to $102.50 minus the exercise price for each share, less withholding, plus one CVR per share. Options priced at $102.50 or more but under $114.50 get one CVR per share and no cash. The proxy says each payment on those CVRs is the amount, if any, by which a milestone payment exceeds an excess exercise price for that milestone, so they can pay less than a share’s CVR, or nothing, even when a milestone is reached. Options priced at $114.50 or more are cancelled for nothing.
• Under Section 2.4(c)(i), RSUs outstanding on August 3, 2026 that have not vested by close vest at close and are cancelled for $102.50 in cash plus one CVR per share, less withholding. Under Section 2.4(c)(ii), RSUs granted after August 3, 2026 become a cash award of $102.50 per share plus one RSU CVR per share, on the same time based vesting schedule.
• PSUs become a cash award of $102.50 for each earned share plus one CVR per earned share, with the earned shares generally set by actual performance as of the last full trading day before the day of close (Section 2.4(b)). The award keeps the PSU’s time based vesting schedule, subject to any accelerated vesting terms in the award. The cash waits for each vesting date and is paid within 20 days after that date if the award vests (Sections 2.4(b) and 2.4(c)). The CVR agreement says a CVR payment tied to a converted PSU award is paid through payroll on the first payroll date on or after the later of the milestone payment date and the award’s vesting date. The FAQ in Lantheus’s August 3, 2026 leader toolkit says its PSUs can pay out from 0% to 200% based on Lantheus stock against an index, and that converted PSUs become payable at vesting, subject to continued employment through the vesting date.
• The same FAQ says that if the deal has not closed by December 1, 2026, the 2026 annual corporate bonus achievement will be determined by the Lantheus Talent and Compensation Committee of the board, with payments made in the normal course, which it gives as March 2027. It also says that an employee whose role is impacted after closing would be eligible for severance under the company policy or as required by local law, and that until closing Lantheus continues to operate as an independent company.
• Option cash, and cash for RSUs outstanding on August 3, 2026, is paid as soon as practicable after close and in no event later than 15 business days after the closing date (Sections 2.4(a) and 2.4(c)). Payments on CVRs tied to options, RSUs or PSUs are made through payroll where the law requires it (Section 2.4(d)), and the CVR agreement treats each such payment as compensation in the year it is paid.
• Under Section 2.4(e), ESPP participation was limited to employees already in the plan the day before the agreement was signed, and contribution rates could not be raised. Lantheus’s quarterly report dated November 5, 2026 says the offering period that ended September 11, 2026 was completed and its shares were issued, that the ESPP was suspended effective that date, and that no new offering period began. Lantheus’s 2023 ESPP says it is intended to qualify under Section 423 of the tax code, with six month offering periods.
• Lantheus’s board approved a $6.0 million transaction bonus pool for certain employees, including certain executive officers. The proxy says the bonuses allocated to two executive officers are payable in cash no later than five business days after the closing date, subject to their continuous service through close. Amended severance letters for certain executive officers clarify that their converted PSUs vest on time alone, with no new performance test, on a qualifying termination within 12 months after close. For 12 months after close, or until an employee’s job ends if sooner, Curium agreed to keep each continuing employee’s base pay and target annual cash bonus opportunity no less favorable than before close, and to provide severance benefits as described in the agreement’s disclosure schedule, which is not public (Section 6.7(a)). The agreement says this gives no employee a right to stay employed and creates no third party rights for employees (Section 6.7(g)).
• The proxy says that under the merger agreement Lantheus may engage an outside firm to run Section 280G and 4999 calculations, and to recommend and implement strategies to mitigate any issues from those sections and maximize the net after tax proceeds for anyone subject to the Section 4999 excise tax.

Sources. The joint Curium and Lantheus release, August 3, 2026. The merger agreement dated August 3, 2026, with the form of CVR agreement as its Exhibit B, filed as Exhibit 2.1 to the Lantheus Form 8-K filed August 4, 2026. The Lantheus definitive proxy statement, September 8, 2026, and the Lantheus leader toolkit for employees, August 3, 2026. Lantheus Forms 8-K on the September 21, 2026 HSR refiling, the October 14, 2026 shareholder vote and the October 21, 2026 Second Request. The Lantheus quarterly report for the quarter ended September 30, 2026, dated November 5, 2026, and the Lantheus 2023 Employee Stock Purchase Plan. BFA Wealth Management isn’t affiliated with Curium, CapVest Partners or Lantheus. The terms and dates above come from the announcement and filings named here, as of the date the facts were checked. They can change before close, so confirm the treatment of your own awards with HR before you act.

In this deal the price is paid in cash, not stock. At close, each Lantheus share you own becomes $102.50 in cash plus one CVR, and the stock stops trading. The cash is generally treated as a sale for tax purposes, with long term rates for shares held more than a year. Options priced under $102.50, and RSUs that were outstanding on August 3, 2026, are paid out in cash too, generally within 15 business days after close. Cash for those RSUs is taxed as pay, and cash for options is generally taxed as ordinary income. Federal withholding on it can be a flat 22%, with 37% required on supplemental pay above $1 million in a year, and that may be less than you owe. Before Your Company Is Sold for Cash covers the cash side, and because Lantheus stock stops trading after close, When Your Company Goes Private applies too.

The CVR is a contract right, not a share. It generally pays nothing unless Lantheus products reach set sales levels after close. The prostate cancer diagnostics, including PYLARIFY, are measured in calendar year 2030, with five steps from $950 million to $1.75 billion in adjusted sales that together pay up to $8.00 per CVR. The neurology diagnostics, including Neuraceq, are measured in any one of 2028, 2029 or 2030, with two steps that together pay up to $3.00. DEFINITY is measured in 2030, with one step that pays $1.00. A step not reached before January 1, 2031 pays nothing, and the release says there can be no assurance that any payments will be made. The last milestone year is 2030, and Curium must fund any payment on it by March 31, 2031. The CVR pays no interest and cannot be sold or transferred except in limited cases, and Curium owes commercially reasonable efforts for the approved products but no set level of effort to develop a product. A CVR can pay no more than $12.00, and it may pay nothing. The $102.50 in cash is the set part of the price, and it still depends on the deal closing.

How the CVR is taxed depends on facts about you. The proxy says the tax treatment of the CVRs is uncertain. For your shares, the CVR may be a closed transaction, where its value at close counts as part of your sale price that year, or an open transaction, where each payment counts when it arrives. Under either one, part of a payment made more than a year after close may be treated as imputed interest, taxed as ordinary income. For CVRs tied to RSUs, PSUs or options, the CVR agreement treats each payment as compensation in the year it is paid. For Section 423 ESPP shares, and shares from exercised incentive stock options, a cash out at close before both holding periods pass is usually a disqualifying disposition, and part of the proceeds is then taxed as ordinary income. For ESPP shares, part of the gain can be ordinary income even when both periods have passed. CVR payments tied to your awards go through payroll where the law requires it. Take the CVR terms and your own records to your tax preparer before you file the return for the year of close, and keep them until the IRS can no longer review the return with the last CVR payment.

Timing matters for PSUs, converted RSUs and the ESPP. Your earned PSU count is generally set by Lantheus stock against its index as of the last full trading day before the day of close, and the cash and CVRs for those shares wait for your vesting dates, so leaving before a vesting date can forfeit that piece unless a severance term speeds it up. RSUs granted after August 3, 2026 work the same way. The treatment at close reaches awards still outstanding at close, so an award that ends with your job before then generally gets none of it, unless your award or severance terms say otherwise. ESPP shares bought on September 11, 2026 come from an offering period that began in March 2026, so they do not pass both holding periods until after March 2028. That is later than the close in the first half of 2027 the companies said they expected, and later than the November 30, 2027 limit on the outside date. The cash from your shares counts in the tax year of close, and the cash for options and RSUs in the year it is paid, which can be the next year if close falls late in the year. That is the part worth planning before close.

1. Which of my RSUs were outstanding on August 3, 2026 and will still be unvested at close, so they vest at close for $102.50 plus one CVR per share, and which were granted after and keep vesting as cash plus a CVR?
2. How many of my PSUs will count as earned at close, and on what date does each converted piece vest and pay?
3. For each option I hold, is the exercise price under $102.50, from $102.50 to under $114.50, or $114.50 and up, and if it is in the middle band, how would the CVR payments on that option be figured for me?
4. If I leave or am let go before or after close, which severance policy covers me, and do my award terms speed up vesting on my converted PSUs and on RSUs granted after August 3, 2026, and for how long?
5. If the deal has not closed by December 1, 2026, how will my 2026 bonus be set and paid, and will any refresh or promotion grant still be made before close?
6. Am I being offered a transaction bonus or a retention package, what does it vest on, and what am I agreeing to by signing it?
7. If I hold ESPP shares, including those bought on September 11, 2026, will they pass the Section 423 holding periods by close, more than two years from the offering date and more than one year from purchase?
8. Should I keep my Lantheus shares to close, which would bring $102.50 plus the CVR if the deal closes, or sell before close, which gives up the CVR on those shares but ends the risk that the deal does not close?
9. Will withholding on the cash at close and after, which can be a flat 22% federal rate, or 37% above $1 million of supplemental pay in a year, cover my bracket, or do I need estimated payments?
10. How will each CVR payment be taxed for me, on my shares and on CVRs tied to my awards, and what records do I keep?
11. Could the golden parachute rules (Section 280G) reach me as an officer, a more than 1% owner or one of the highest paid 1% of employees, and would my deal payments reach three times my base amount, where a 20% excise tax can apply?
12. What happens to my awards and my shares if the deal does not close by the outside date, and what would I do then?

Nobody at your company is paid to answer these for you. HR will tell you the mechanics. Your CPA will handle the return. The person who puts it all on one page, in the order it matters, is usually missing. That is the gap we fill.