Section 1256 contracts

Definition

Section 1256 of the tax code gives certain contracts — regulated futures, options on futures, BROAD-BASED index options (SPX, and cash-settled index options generally), and certain FX contracts — a distinct regime: MARK-TO-MARKET at year-end (open positions are taxed as if closed at December 31 fair value) and the 60/40 RULE (60% of gains/ losses treated as long-term, 40% short-term, regardless of holding period — even intraday). Facts, never advice: the regime materially changes after-tax outcomes for short- horizon strategies and exempts these contracts from the wash-sale rule.

How it works / structure

• The covered set (engine-executable classification): regulated futures contracts (all the platform’s futures — instrument-equity-index-futures through the complexes), options on futures, broad-based index options (SPX/XSP/ NDX-style cash-settled — the SPY-vs-SPX distinction is a TAX distinction: SPY options are equity options under the standard regime, SPX options are 1256), and foreign currency contracts per §1256(g) (ext-fx futures). Single-stock and narrow-based products are NOT covered.
• 60/40 arithmetic: a day trader’s futures gain is taxed 60% at long-term rates + 40% short-term — a blended rate materially below all-short-term treatment at typical brackets; the identical strategy on SPY options pays all-short-term (the documented reason index-options and futures strategies quote after-tax advantages — opt-0dte-mechanics SPX-vs-SPY choice has a tax leg).
• Mark-to-market and its features: year-end open positions realize for tax (no deferral control — a December drawdown in an open position is a realized tax loss and vice versa); NO WASH-SALE RULE applies (acct-wash-sale exemption — re-entry cadences are unconstrained); loss carryback election (3 years, against prior 1256 gains — Form 6781 mechanics, a feature almost nothing else in the individual code offers).
• Reporting: Form 6781, aggregate broker-reported marks — mechanically simpler than lot-matched equity accounting.

When it applies

Instrument selection where economically-equivalent choices differ only in wrapper (SPX vs SPY options, index futures vs index ETFs — the platform quotes the after-tax replay per wrapper as facts); short-horizon strategy tax modeling (the 60/40 blend is the difference); year-boundary planning mechanics (mark-to-market removes deferral as a lever — stated, not advised).

Risk profile & failure modes

• Classification errors: narrow-based vs broad-based index boundaries, and ETF options (NOT 1256 even on index ETFs) — misclassification propagates through every after-tax number; the engine pins classification per instrument from primary sources.
• Mark-to-market surprises: taxes due on open-position gains without a cash-realizing sale — funding facts the year-end scenario must include.
• The 40% floor: 1256 treatment cannot convert everything to long-term — comparisons against buy-and-hold equity (100% long-term at qualification) flip sign at long horizons; the wrapper advantage is cadence-dependent, stated per replay.
• Jurisdiction/status edge cases: dealer status, mixed straddles (§1092 interactions — acct-assignment-tax), and state treatment differences are flagged to professionals by design.

Evidence & limits

The statute and Form 6781 instructions are primary sources (cited). Blended-rate arithmetic is mechanical at stated bracket assumptions — the platform computes it per user- supplied assumptions and asserts no individual’s outcome. Everything here is mechanics; wrapper-choice recommendations remain conditional facts, never advice.

Falsifiable-thesis examples

Illustrations only, not signals:

• “Strategy S run in SPX options produces a higher after-tax replay return than in SPY options at the assumed brackets (wrapper-arithmetic check)” — falsified by the paired computation.
• “This futures book’s year-end mark-to-market tax liability stays within its reserved cash (funding audit)” — falsified by the year-end scenario.

Cross-references

• The exemption it grants: acct-wash-sale
• The regime it contrasts: acct-assignment-tax (equity- option character rules)
• The instruments it covers: instrument-equity-index-futures, the futures complexes, ext-fx
• The live wrapper choice: opt-0dte-mechanics (SPX vs SPY); container context: acct-account-types