MLP tax season is different. K-1s arrive late, basis tracking is your responsibility, and multi-state filing can catch you off guard. Here's the complete timeline and action list.
By Lucas Andersen — Last updated April 9, 2026
| Month | Action Items |
|---|---|
| January | Gather prior-year K-1s for starting basis. Locate original purchase confirmations. Download broker 1099 composites when available. |
| February | Register for K-1 alerts at taxpackagesupport.com. Verify no position changes (buys/sells) are unaccounted for. Review broker distribution records against prior K-1 Box 19A. |
| Early March | EPD K-1s typically available (historically first week of March). Download and verify EIN matches prior year. Begin basis calculations. |
| Mid-March | ET K-1 package (3 K-1s: ET, USAC, SUN) typically available. MPLX, WES, PAA K-1s usually arrive. Partnership filing deadline: March 15. |
| Late March–April | Late-filer K-1s arrive. If any K-1 is missing, prepare Form 4868. Deadline: April 15 (payment + extension). |
| May–June | File return once all K-1s are in hand. Check for amended K-1s from partnerships that filed extensions. |
| July–September | Monitor for amended K-1s. Assess materiality of any changes. File 1040-X only if amendment affects tax liability. |
| October 15 | Extension deadline. File your return. No further extensions available without IRS approval. |
Start by locating every prior-year K-1 for every MLP you held during the tax year. These provide the starting outside basis for the current year’s computation. If you’ve lost prior K-1s, request copies through taxpackagesupport.com or call the partnership’s investor relations line. Without prior-year K-1s, your basis calculation for the current year is unreliable.
Download your broker’s year-end distribution summary and reconcile it against K-1 Box 19A (distributions) from the prior year. Discrepancies between broker-reported distributions and K-1-reported distributions are common — the K-1 controls for tax purposes.
Register for email alerts at taxpackagesupport.com for each MLP you own. This is the delivery platform most large MLPs use. You’ll receive a notification the day your K-1 becomes available for download. See 2026 K-1 release dates for typical timing by ticker.
When each K-1 arrives, run through this verification checklist:
1. EIN match. Confirm the partnership EIN matches the prior year’s K-1. A different EIN may indicate a restructuring (TRGP and MMP unitholders experienced this during their conversions to C-corps).
2. Box 19A reconciliation. Compare K-1 Box 19A (distributions) against your broker’s reported distributions. Minor rounding differences are normal. Material differences (>$10) warrant investigation.
3. Box 1 sign. Note whether Box 1 (ordinary business income/loss) is positive or negative. A positive Box 1 increases your taxable income for the year. A negative Box 1 generates a suspended passive loss under §469(k) if you have no other income from that same PTP.
4. Item K liabilities. Check Item K for your share of partnership liabilities. Liability changes affect your outside basis. An increase raises basis; a decrease reduces it. Large liability swings (common during MLP refinancings) can trigger unexpected basis adjustments.
5. Box 20 Code Z (§199A). Look in the supplemental statement for Box 20 Code Z, which reports your qualified business income (QBI) for the §199A deduction. This line is frequently on the supplemental pages, not the K-1 face. TurboTax requires separate entry.
6. Save for basis continuity. Store every K-1 permanently. You need the complete K-1 history from purchase through sale to compute your IRS-adjusted basis. Use the K-1 Basis Tracker to maintain a running calculation.
All K-1s received, no sales during the year: Enter K-1 data into your tax software and file. Straightforward.
Missing one or more K-1s: File Form 4868 for an automatic 6-month extension to October 15. Pay at least 100% of prior-year tax (110% if AGI exceeds $150,000) by April 15 to avoid underpayment penalties.
Sold MLP units during the year: You need the final-year K-1 with the Sales Schedule to determine your §751 ordinary income. Calculate your IRS-adjusted basis for Form 8949 using the basis tracker. Do not rely on the 1099-B basis — it is almost certainly wrong. See why your broker’s cost basis is wrong.
Filed early and K-1 differs from estimate: Assess materiality. If the difference changes your tax liability by more than a trivial amount, file Form 1040-X. This is why extensions are preferable to estimating.
Save all K-1s in your permanent tax records. You will need the complete history when you eventually sell. Amended K-1s can arrive through June or later — monitor your email alerts. If an amended K-1 arrives after you’ve filed, compare it to the original. File 1040-X only if the changes affect your tax liability.
Verify whether any K-1 triggered non-resident state filing obligations. Each K-1’s supplemental statement includes a state income allocation schedule. States with sourced income above their filing threshold require a non-resident return. EPD reports income in approximately 20 states; ET in approximately 41.