Key Insight
K-1 season runs from mid-February through April 15 — and beyond, if you file an extension. This checklist covers everything an MLP investor needs to do, in order, from the day your K-1 arrives to the day you file.
Step one after your K-1 arrives: calculate your real cost basis
Your broker's basis is wrong. Enter your K-1 data and see the IRS-adjusted number — before you file.
In the K-1 tracker, typing your numbers in uploads nothing; an uploaded K-1 PDF is read by a third-party AI provider. Privacy
Open K-1 Basis Tracker (free)Before Your K-1 Arrives (January–February)
Tax season for MLP investors starts well before any forms arrive. The work you do now determines whether April is manageable or chaotic. Most of these steps take less than an hour — but skipping them creates weeks of scrambling later.
Gather purchase records
For each MLP position, locate your original purchase date, price per unit, and number of units. If you made multiple purchases, each lot has its own basis. Check your broker's trade confirmations — these are the numbers everything else builds from.
Locate last year's K-1s
You need last year's ending basis as this year's starting basis. If you tracked basis previously, pull up your records. If not, this is the year to reconstruct — contact Tax Package Support for each MLP to request historical K-1s you may have lost.
Verify your positions haven't changed
Any buys or sells during 2025 affect how the K-1 is processed. If you added units mid-year, that lot has a different holding period and pro-rated K-1 allocations. If you sold, your final K-1 includes a Sales Schedule you'll need for Form 8949.
Check your broker's distribution records
Pull the total distributions received per MLP for 2025. You'll cross-check this against Box 19A on your K-1 when it arrives. Discrepancies usually mean a timing difference or a missed payment — catch them early.
Register at Tax Package Support for each MLP
Most major MLPs use Tax Package Support (taxpackagesupport.com) to distribute K-1s. Register with your social security number and you'll get email alerts the moment your K-1 is posted — no more checking every week. See our 2025 K-1 Release Dates page for the expected schedule for every major MLP.
Get Notified When Your K-1 Arrives
We'll email you the day your MLP K-1 is posted — with a direct link to download it and a walkthrough for entering it.
One email per K-1 release. No spam. Unsubscribe anytime.
When Your K-1 Arrives (March–April)
K-1s for most major MLPs are posted between late February and mid-April. When yours arrives, don't just file it away — there are specific items to verify before you enter anything into your tax software.
Verify the K-1 is for the correct tax year and entity
Check the tax year in Part I and the partnership name in Part II. This is especially important for Energy Transfer investors who receive three separate K-1s (ET, USAC, Sunoco LP) — each must be processed independently.
Check Box 19A (distributions)
Does Box 19A match the total distributions your broker recorded for this MLP in 2025? If not, investigate — the difference may be a timing issue (Q4 distribution paid in January), a reinvested distribution, or a data error worth contacting the MLP about.
Note Box 1 (ordinary income/loss)
This is the primary basis adjustment. A positive number increases your basis; a negative number (shown in parentheses) decreases it. Most midstream MLPs report modest income or loss here — the bulk of basis erosion comes from the distribution exceeding allocated income.
Check Item K (partner's share of liabilities)
Compare the beginning-of-year and end-of-year liability amounts. An increase in your share of liabilities increases your basis; a decrease reduces it. This is one of the adjustments brokers never see and never account for.
Review the supplemental statement
The supplemental pages contain Box 20 codes (including Section 199A information), state-by-state income allocation percentages for multi-state filing, and other detail that doesn't fit on the main K-1 form. Don't skip these pages — they drive state filing obligations and additional federal deductions.
Download and save a copy
Save the K-1 PDF to a permanent location — you'll need this K-1 for future basis tracking. Every year's ending basis depends on every prior year's K-1. Losing a K-1 from five years ago means reconstructing basis from scratch when you eventually sell.
Update Your Basis
Enter this year's K-1 data and see your updated IRS-adjusted basis instantly. Free, no signup required.
In the K-1 tracker, typing your numbers in uploads nothing; an uploaded K-1 PDF is read by a third-party AI provider. Privacy
Open K-1 Basis TrackerBefore You File (April)
Once you have all your K-1s in hand, there's still work to do before you file — or before you decide to extend. This is where most MLP investors make expensive mistakes.
Calculate your updated basis
Apply all K-1 adjustments to last year's ending basis using the IRS Partner's Basis Worksheet methodology. This means income allocations, distributions, liability changes, deductions, and any other items from the K-1 — all 18 lines of the worksheet, in order.
Check if your basis is approaching zero
If your adjusted basis is near zero, excess distributions may be taxable as capital gain under IRC Section 731 — even if you haven't sold. This catches many long-term MLP holders by surprise. Know your number before it's too late to plan.
Verify your broker's 1099-B basis (if you sold)
Compare the 1099-B basis to your K-1-adjusted basis. They will almost certainly differ — your broker's number hasn't been adjusted for any K-1 activity. You'll need to override it on Form 8949.
Identify state filing obligations
Review your K-1 supplemental statement for state-source income above de minimis thresholds. Many MLP investors owe non-resident state returns in states where the pipeline operates — and most don't realize it until the state sends a notice.
Decide: file now or extend?
If any K-1 is still missing, file Form 4868 for an automatic six-month extension. There is no penalty for extending — only for not paying estimated tax by April 15. When in doubt, extend.
Warning
If you sold MLP units in 2025, do NOT rely on your broker's 1099-B basis. It hasn't been adjusted for any K-1 activity. You must report the K-1-adjusted basis on Form 8949 with code B in column (f) — indicating the broker's reported basis is incorrect — and your adjustment amount in column (g). See our broker basis article for the full explanation.
Filing Decisions
Your filing path depends on two factors: whether all K-1s have arrived and whether you sold units during the year. Here's the decision tree.
All K-1s received + no sales
Enter K-1 data in TurboTax or your tax software. Update your basis worksheet for each MLP position. File your federal return and any required state non-resident returns. This is the simplest scenario.
All K-1s received + sold units
Calculate your K-1-adjusted basis for the sold position. Prepare Form 8949 with the broker's basis in Column (e) and your adjustment in Column (g) using adjustment Code B (basis reported to IRS is incorrect). Code B applies regardless of holding period — short-term vs long-term is determined by which Part of Form 8949 (I or II) the row goes on, not by the adjustment-code letter. Include Section 751 recapture as ordinary income if applicable (check the Sales Schedule in your K-1 package). Then file.
Missing K-1s
File Form 4868 for an automatic extension to October 15. Pay estimated tax by April 15 — use last year's K-1 data as a baseline. Wait for all K-1s to arrive, then complete your basis calculations and file. This is what most experienced MLP investors do every year.
K-1 arrives after filing
Compare the actual K-1 to whatever estimates you used when filing. If the numbers are materially different — different enough to change your tax liability by more than a trivial amount — file Form 1040-X (amended return). This is exactly why extensions are preferable to estimating.
Amended K-1 received
MLPs occasionally issue corrected K-1s — sometimes months after the original. If the amended K-1 is materially different from the original and you've already filed, you may need to file Form 1040-X. Compare every line; amended K-1s sometimes change only one number, but that number may affect your basis, state filings, or Section 199A deduction.
Key Insight
The extension is free. Filing Form 4868 costs nothing and gives you six extra months. The only requirement is that you pay your estimated tax liability by April 15. If you overpay, you get a refund when you file. If you underpay slightly, the interest is minimal compared to the cost of amending a return filed with wrong numbers.
After Filing
Filing your return isn't the end of the MLP tax cycle. The records you maintain now become next year's starting point — and the year after that. Basis tracking is cumulative, and every gap you leave today compounds into a larger problem later.
Save this year's K-1 and your basis calculation
Next year starts from this year's ending basis. Store the K-1 PDF and your completed basis worksheet together — whether that's in a folder on your computer, a tax file, or the K-1 Basis Tracker's built-in export. Future-you will thank present-you.
Update your records with ending basis, suspended losses, and liability amounts
Your ending basis, any suspended passive losses under IRC Section 469(k), and your ending share of liabilities (Item K) all carry forward to next year. Record them now while the numbers are fresh — reconstructing from a K-1 you half-remember is error-prone.
Watch for amended K-1s
MLPs occasionally issue corrected K-1s through September or even later. Keep an eye on Tax Package Support notifications. If an amended K-1 arrives with material changes, you may need to update your basis calculation and potentially file Form 1040-X.
Reconcile if you filed early with estimates
If you filed before all K-1s arrived and used estimated numbers, compare each actual K-1 to your estimates as they arrive. If the actual data differs materially, file Form 1040-X for the affected tax year. Don't let this linger — the sooner you amend, the less interest accrues.
Monitor distribution changes for next year
Distribution increases (or cuts) directly affect how fast your basis erodes. If your MLP announces a distribution increase, your basis will erode faster next year — which means you're closer to the point where distributions become taxable even without selling. Track it proactively.
Don't Wait Until Next Tax Season
Track your MLP basis now while the K-1 data is fresh. Waiting makes it harder — and more expensive if you need professional help.
In the K-1 tracker, typing your numbers in uploads nothing; an uploaded K-1 PDF is read by a third-party AI provider. Privacy
Check Your Basis NowFrequently Asked Questions
Most MLP K-1s arrive between late February and mid-April. If you haven't received all K-1s by mid-April, file Form 4868 for an automatic six-month extension. You owe no penalty for filing an extension as long as you pay estimated taxes by April 15. Filing with estimated K-1 data (instead of waiting) creates amendment risk.
Not necessarily. If all your K-1s arrive before mid-April and you have time to process them, you can file by the deadline. But most MLP investors file extensions as standard practice — it's free, gives you until October 15, and avoids the risk of filing before all K-1s arrive.
If you filed with estimated numbers and receive an actual K-1 that differs, you need to file Form 1040-X (amended return). This is why extensions are generally preferable to estimating — the amendment process is time-consuming and may trigger additional scrutiny.
Use last year's K-1 data as a baseline. If distributions and income were similar, your tax liability should be comparable. Pay at least 100% of last year's total tax (110% if AGI > $150,000) by April 15 to avoid underpayment penalties, then reconcile when you file in October.
Keep every K-1 from every year of ownership, your original purchase confirmations (date, price, shares), your running basis calculation, all distribution records, and any 1099-B from sales. Keep records for at least 3 years after selling your last MLP unit — the IRS can audit up to 3 years back (6 years if substantial understatement).
Yes. You can file your federal return on time and file state non-resident returns later (or vice versa). Each jurisdiction has its own deadline. However, most MLP investors find it simpler to extend everything and file all returns together once all K-1s arrive.
Disclaimer: This content is for educational and informational purposes only. It does not constitute tax, legal, or financial advice. MLP taxation involves complex rules including basis tracking, §751 recapture, passive activity limitations, and multi-state filing. Consult a qualified tax professional before making tax or investment decisions.
Lucas Andersen is not a CPA, Enrolled Agent, or tax attorney. Information reflects rules as of the date published and may change. Always verify with current IRS guidance.