The difference between a split-off and a spin-off comes down to whether you have to do anything. In a spin-off, the parent company hands every shareholder a proportional slice of the subsidiary automatically, so you walk away holding two stocks instead of one. In a split-off, the parent runs a tender offer: you choose whether to trade some or all of your parent shares for subsidiary shares, and the exchange is voluntary. Both can qualify as tax-free under Internal Revenue Code Section 355, but they land on your account statement and your tax basis in very different ways.
What Happens in a Spin-Off
The parent company picks a record date and distributes shares of the subsidiary to everyone who owns parent stock on that date. The distribution is proportional. Own 1% of the parent, receive 1% of the distributed subsidiary shares. You don’t sign anything, elect anything, or spend anything. The new shares just show up in your brokerage account.
Afterward you hold two separate public companies. Your parent share count is unchanged, though the parent’s price typically drops to reflect the value it shed. The subsidiary trades on its own with its own board and management.
What Happens in a Split-Off
A split-off is structured as a tender offer. The parent invites shareholders to swap some or all of their parent shares for subsidiary shares, and participation is optional. Because not everyone participates, the distribution isn’t proportional across the shareholder base. Some investors swap in, others keep their parent stock, and the ownership of each company shifts accordingly.
Companies often sweeten the exchange to pull shareholders in, letting each tendered parent share convert into slightly more than a dollar of subsidiary stock. In the 2023 Johnson & Johnson/Kenvue split-off, participating shareholders got roughly a 7% discount on the exchange ratio.
If demand outruns the offer, the exchange is oversubscribed and proration kicks in. The parent accepts only a fraction of what was tendered, applied proportionally among participants. In the JNJ/Kenvue exchange, the final proration factor was about 23.2%, so the company accepted roughly a quarter of the shares eligible holders tendered.1Johnson & Johnson. Johnson and Johnson Announces Final Results of Exchange Offer and Finalizes Separation of Kenvue Inc Shares that aren’t accepted are returned.
From the parent’s side, a split-off doubles as a buyback. The tendered shares get retired, so the parent’s outstanding share count drops. In a spin-off it doesn’t.
Split-Off vs Spin-Off at a Glance
- What you have to do: Nothing in a spin-off. In a split-off, you decide whether to tender.
- What you end up holding: Both stocks after a spin-off. One or the other (or a mix) after a split-off, depending on how much you tendered.
- Parent share count: Unchanged in a spin-off. Reduced in a split-off, because tendered shares are retired.
- Proration risk: Only split-offs can be oversubscribed and prorated.
- Exchange premium: Split-offs often include one as an incentive. Spin-offs don’t.
- Basis math: A spin-off splits your original basis across two stocks by market value. A split-off substitutes the basis of the surrendered shares into the new ones.
Your Tax Basis After a Spin-Off
Because a spin-off adds a stock without taking one away, your original cost basis has to be divided between the two holdings. The tax code treats the spin-off as though you surrendered your parent shares and received both the parent and subsidiary shares back in an exchange, and then requires you to allocate your total basis across what you now hold.2Office of the Law Revision Counsel. 26 USC 358 Basis to Distributees
The split is based on relative fair market values right after the separation. If the parent represents 70% of the combined post-spin-off value and the subsidiary 30%, you assign 70% of your old basis to the parent and 30% to the subsidiary. Your total basis doesn’t change. It’s just divided into two buckets, each with a lower per-share basis than you started with.
Companies have to file IRS Form 8937 reporting the effect of the separation on shareholder basis, including the data behind the allocation.3Internal Revenue Service. Instructions for Form 8937 Most parents post it on their investor relations page shortly after the separation. If your broker doesn’t adjust basis automatically, that form gives you the percentages.
Your Tax Basis After a Split-Off
The math here is cleaner. You surrendered specific parent shares in exchange for subsidiary shares, so the basis of the subsidiary stock you received equals the adjusted basis of the parent stock you gave up.2Office of the Law Revision Counsel. 26 USC 358 Basis to Distributees No proportional allocation. If you tendered parent shares with a $5,000 total basis, your new subsidiary shares carry $5,000 in basis.
If you only tendered part of your parent position, the untendered shares keep their original basis untouched. The substitution is administratively simple on the back end. The harder part is deciding whether to tender at all.
Tax-Free Treatment Under Section 355
Both transactions are structured to qualify as tax-free under Section 355. When the requirements are met, neither the corporation nor its shareholders recognize gain or loss on the distribution or exchange.4Office of the Law Revision Counsel. 26 US Code 355 – Distribution of Stock and Securities of a Controlled Corporation The statute applies whether the distribution is proportional or involves a surrender of stock, so the spin-off/split-off choice doesn’t by itself change the tax outcome.
Qualifying is not automatic. Section 355 imposes conditions on the parent, the subsidiary, and the structure of the deal, and corporate planners spend months engineering around them. As a shareholder you don’t influence any of that. What you need to know is whether the deal was designed to qualify, which the parent’s announcement and Form 8937 will state directly.
If the Separation Doesn’t Qualify
If a spin-off fails Section 355, the fair market value of the distributed subsidiary stock is treated as a taxable distribution. To the extent the parent has accumulated earnings and profits, it’s taxed as a dividend at ordinary rates. Any excess reduces your basis, and anything beyond that is capital gain.5Office of the Law Revision Counsel. 26 USC 356 Receipt of Additional Consideration
A failed split-off is treated as a stock redemption. You’d calculate gain or loss on the difference between the fair market value of the subsidiary shares received and the adjusted basis of the parent shares you surrendered.
Cash for Fractional Shares
Distribution ratios rarely produce whole numbers. If a spin-off entitles you to 47.3 subsidiary shares, you’ll typically receive 47 shares plus cash for the fractional 0.3. The company sells all fractional entitlements in bulk and distributes the proceeds proportionally.
Even in a tax-free separation, that cash is taxable. When an exchange includes money or property beyond the permitted stock (known as “boot”), you recognize gain up to the amount of cash received.5Office of the Law Revision Counsel. 26 USC 356 Receipt of Additional Consideration For a fractional-share payment, that’s a small capital gain calculated using the basis allocated to the fraction. The amount is usually minor, but your broker will report it on a 1099-B, so leaving it off your return can trigger an IRS mismatch notice.
Holding Period on the New Shares
Your clock carries over. Under Section 1223, when stock received in a Section 355 distribution has the same basis (in whole or in part) as the stock you held before, the holding period of the new shares includes the time you held the original parent shares.6Office of the Law Revision Counsel. 26 US Code 1223 – Holding Period of Property
If you bought parent stock three years ago and receive subsidiary shares today through either a spin-off or a split-off, those new shares are already long-term holdings. Any gain on a later sale qualifies for the long-term capital gains rate. You don’t restart the clock.
The choice between a spin-off and a split-off belongs to the company. What you control is how you respond: whether to tender in a split-off, how to adjust your basis records after either one, and how to report the cash on fractional shares. The parent’s Form 8937 and investor relations materials will carry the specific numbers you need once the separation closes.