Options assignment & tax mechanics

Definition

Options generate tax events with mechanics that surprise equity intuition: premiums are not taxed when received but when the position RESOLVES (expiry, close, or assignment); assignment FOLDS the option into the stock transaction (adjusting basis or proceeds rather than standing alone); holding periods can be suspended or reset by option positions against stock; and the straddle rules (IRC §1092) defer losses on offsetting positions. Facts, never advice: the engine computes these resolutions because after-tax results diverge from P&L without them.

How it works / structure

• The resolution table (engine-executable, per Pub 550): short option expires worthless → premium is short-term gain at expiry; short option closed → gain/loss at close; SHORT CALL ASSIGNED → premium ADDS to stock sale proceeds (the stock sale’s character/holding period governs); SHORT PUT ASSIGNED → premium REDUCES the acquired stock’s basis (no separate premium event); long option exercised → premium folds into the stock’s basis (calls) or proceeds (puts).
• Holding-period interactions: buying a protective put on stock held short-term RESETS/suspends the stock’s holding period (the married-put and short-sale rules); QUALIFIED vs unqualified covered calls (deep-ITM calls suspend the stock’s holding period and can disqualify dividend treatment — the qualified-covered-call rules are strike-and-tenor mechanical, strategy-covered-call economics carry a tax shadow).
• Straddle rules (§1092): offsetting positions (collars and similar) defer realized losses to the extent of unrealized gains in the offsetting leg — defined-risk structures can trap losses across tax years.
• The character baseline: most single-stock option outcomes are short-term (taxed as ordinary rates) regardless of how long the OPTION was held short — contrast acct-section-1256’s 60/40 treatment on broad-based index options.

When it applies

Every taxable options account: premium-selling programs (the resolution table IS their tax accounting — strategy-wheel cycles fold premiums into stock basis repeatedly); covered-call books (qualification mechanics); collars and spreads (straddle-rule exposure); assignment handling (mgmt-assignment-handling — the tax consequence is part of the decision’s facts).

Risk profile & failure modes

• Phantom-differences between P&L and tax: a wheel cycle’s replay P&L and its tax picture diverge through basis-folding — reconciliation is structural, not optional.
• Holding-period sabotage: a protective put purchased days before long-term status resets the clock — a mechanical, dated, preventable event the engine flags.
• Straddle-rule surprises: harvesting the losing leg of a collar while the winning leg has unrealized gains defers the loss — the December mechanics interact with acct-wash-sale windows.
• Qualified-covered-call boundary: strike selection a few dollars too deep flips qualification — a parameter check, not a judgment call.

Evidence & limits

Pub 550 and §1092 are the primary sources (cited); the resolution table restates their mechanics. Edge configurations (mixed straddles, dealer status) are beyond the entry’s scope and flagged to professionals by design. Nothing here is advice; the engine computes flags and after-tax replays, and defers judgment to the user’s tax professional.

Falsifiable-thesis examples

Illustrations only, not signals:

• “This wheel program’s after-tax replay diverges from pre-tax by more than 2% annualized at assumed rates (folding-mechanics measurement)” — falsified by the paired accounting.
• “No position in this book suspends a stock holding period within 30 days of long-term qualification (clock audit)” — falsified by the flag scan.

Cross-references

• The mechanical trigger: mgmt-assignment-handling, ms-expiration-exercise-assignment
• The loss-window sibling: acct-wash-sale
• The contrasting regime: acct-section-1256 (60/40, mark-to-market)
• The strategies shadowed: strategy-covered-call, strategy-wheel, strategy-collar