DuPont spinoff cost basis calculations start from a simple rule: the spinoffs themselves were tax-free under Internal Revenue Code Section 355, so you didn’t owe tax when the new shares landed in your account, but you did have to carve up your original basis across each resulting company using DuPont’s published allocation percentages. Your total basis never changes. It just gets divided, and every later sale depends on getting the division right.
The Transactions That Reshaped Your Basis
If you’ve held since the merger, four separate events have touched your basis.
Dow Chemical and E.I. du Pont de Nemours merged on August 31, 2017 to form DowDuPont (DWDP).1DuPont de Nemours, Inc. DowDuPont Merger Successfully Completed On April 1, 2019, DowDuPont distributed one share of Dow Inc. (DOW) for every three DWDP shares.2Dow Investor Relations. Dow Completes Separation from DowDuPont On June 1, 2019, it distributed one share of Corteva (CTVA) for every three DWDP shares, then renamed itself DuPont de Nemours (DD) and executed a 1-for-3 reverse stock split.3Securities and Exchange Commission. DuPont de Nemours, Inc. Form 8-K Most recently, on November 1, 2025, DuPont completed the spinoff of Qnity Electronics (QNTY) at a ratio of one Qnity share for every two DD shares.4DuPont de Nemours, Inc. DuPont Completes Separation of Qnity Electronics
All of these distributions were structured as tax-free reorganizations under Sections 355 and 368(a)(1)(D).5DowDuPont, Inc. Distribution of Dow, Inc. Common Stock – Attachment to Form 8937 The IRS lets that happen only if you preserve your basis by reallocating it, not by getting a fresh $0 basis in the new shares.
Allocating Your Original DowDuPont Basis
The IRS requires the split to be made using the relative fair market values of each stock right after the distribution. DuPont published specific percentages, derived from trading prices on the second trading day after each spinoff, in the Form 8937 filings on its investor relations site.
Step 1: The Dow Distribution
For the April 1, 2019 Dow spinoff, allocate 33.5620% of your total DowDuPont basis to your new DOW shares. The remaining 66.4380% stays with the DowDuPont shares.5DowDuPont, Inc. Distribution of Dow, Inc. Common Stock – Attachment to Form 8937
Step 2: The Corteva Distribution
For the June 1, 2019 Corteva spinoff, take the basis that remained with DowDuPont after Step 1 and allocate 25.86805% to your CTVA shares. The remaining 74.13195% stays with the DD shares.6DuPont de Nemours, Inc. Form 8937 – Corteva Spin-Off and Reverse Stock Split Basis Allocation
Step 3: The Reverse Stock Split
The 1-for-3 reverse split immediately after the Corteva distribution reduced your DD share count to a third of what it was. Your total DD basis stayed the same, so the basis per share tripled.
Step 4: The Qnity Distribution
The November 1, 2025 Qnity separation was also structured under Section 355, so you again split the current DD basis between DD and QNTY using the percentages in DuPont’s Form 8937 for that transaction. Consult that filing directly for the exact figures when preparing your 2025 return.
A Worked Example Through the 2019 Split
Say you held 300 shares of DowDuPont with a total basis of $3,000, or $10 per share.
- Dow spinoff: You receive 100 shares of DOW (300 ÷ 3). Basis allocated to DOW = $3,000 × 33.5620% = $1,006.86, or about $10.07 per DOW share. Remaining DowDuPont basis = $3,000 × 66.4380% = $1,993.14.
- Corteva spinoff: You receive 100 shares of CTVA (300 ÷ 3). Basis allocated to CTVA = $1,993.14 × 25.86805% = $515.56, or about $5.16 per CTVA share. Remaining DuPont basis = $1,993.14 × 74.13195% = $1,477.58.
- Reverse split: Your 300 DuPont shares become 100 shares of DD. Total DD basis stays at $1,477.58, so the per-share basis is now $14.78.
The three pieces reconcile: $1,006.86 + $515.56 + $1,477.58 = $3,000. If the sum doesn’t match your original basis, check the math. Rounding of a few cents is normal; larger gaps mean an error.
Cash Received in Lieu of Fractional Shares
If your DowDuPont share count wasn’t evenly divisible by three, you were entitled to a fractional share of DOW or CTVA. DuPont sold the fraction and sent you cash instead. The IRS treats that cash as a sale of the fractional share, so you report a capital gain or loss.5DowDuPont, Inc. Distribution of Dow, Inc. Common Stock – Attachment to Form 8937
Take the cash you received as your proceeds, subtract the cost basis that would have been assigned to the fractional share, and report the result on Form 8949.7Internal Revenue Service. Instructions for Form 8949 The same treatment applies to fractional-share cash from the Qnity distribution.
If You Tendered Shares in the 2021 IFF Exchange
DuPont’s 2021 merger of its Nutrition & Biosciences business with International Flavors & Fragrances was structured as a split-off, not a pro-rata distribution. It only affects your basis if you actively tendered DD shares in the exchange offer. If you didn’t participate, your DD holdings and basis were untouched.
If you did tender, 100% of the basis in the DD shares you surrendered carried over to the IFF shares you received. The per-share basis shifted with the exchange ratio: each IFF share has a basis equal to approximately 139.2758% of the per-share basis of the DD shares you gave up.8DuPont de Nemours, Inc. Report of Organizational Actions Affecting Basis of Securities – N&B Distribution Cash in lieu of fractional IFF shares is reported the same way as the earlier spinoffs.
One boundary worth noting: DuPont’s November 2022 sale of most of its Mobility & Materials segment to Celanese was a corporate asset sale for cash.9DuPont. DuPont Completes M&M Divestiture to Celanese Shareholders received no stock and have no basis adjustment or reporting obligation from that transaction.
Holding Period Tacks Back to Your Original Purchase
Shares received in a Section 355 distribution inherit the holding period of the parent stock.10eCFR. 26 CFR 1.1223-1 – Determination of Period for Which Capital Assets Are Held Your holding period for DOW, CTVA, current DD, and QNTY all trace back to the date you bought your original DowDuPont (or pre-merger Dow or old DuPont) shares. You don’t restart the clock on distribution dates.
This matters when you sell. Long-term capital gains rates apply to positions held more than a year, counted from that original purchase, not from the spinoff date. For most shareholders who’ve held through the whole chain, everything qualifies for long-term treatment.
Reporting the Gain or Loss When You Sell
Once you sell, gain or loss equals your proceeds minus the allocated basis you calculated above. Report the sale on Form 8949 and Schedule D. If your brokerage’s basis figure doesn’t match your worksheet, use your own figure and be prepared to substantiate it; brokers frequently miss one or more of the intermediate allocations, especially for shares transferred between accounts.
Records You Need to Keep
Hold on to every Form 8937, brokerage statement, and basis worksheet for as long as you own any of the resulting shares, plus at least three years after you file the return for the year you finally sell. The IRS requires that when you receive property in a nontaxable exchange, you retain records on the old property until the statute of limitations expires for the year you dispose of the new property.11Internal Revenue Service. How Long Should I Keep Records
For long-term holders, that documentation trail runs back to the original DowDuPont purchase, or further if you owned pre-merger Dow Chemical or old DuPont. Pull the Form 8937 PDFs from DuPont’s investor relations page now and save them with your tax records. Reconstructing the math years later, during an audit or in the middle of a sale, is far harder than saving the source documents while they’re easy to find.