Index Options: SPX, NDX, RUT, and XSP Guide

Index options give traders a direct way to express a view on the broad market, technology leadership, or small-cap performance without selecting individual stocks. But SPX, NDX, RUT, and XSP contracts are not interchangeable: they differ in underlying exposure, contract size, trading hours, expiration choices, and the way profits and losses settle. Understanding those details is essential before using index options for hedging, income strategies, defined-risk trades, or systematic portfolio management.

This guide breaks down how the major U.S. index option products work and where each may fit. You’ll learn the practical differences between SPX options tied to the S&P 500, NDX options on the Nasdaq-100, RUT options on the Russell 2000, and smaller XSP contracts designed around one-tenth the SPX index value. We’ll also cover cash settlement, European-style exercise, weekly and daily expirations, tax considerations, and why sizing matters. Finally, you’ll see what traders should evaluate when automating index-option strategies, from liquidity and execution to expiration-day risk and position management.

What Are Index Options?

Index Options Defined

Index options are derivative contracts whose value is based on a market index level rather than the stock price of a single company. The underlying reference may be a broad equity benchmark, such as the S&P 500 Index for SPX options, the Nasdaq-100 Index for NDX options, or the Russell 2000 Index for RUT options. Because an index represents a defined basket of securities, an index option gives the trader exposure to the aggregate movement of that basket.

A call option generally expresses a bullish view: its value tends to increase when the index rises. A put option generally expresses a bearish view or provides downside insurance: its value tends to increase when the index falls, subject to time decay, implied-volatility changes, and other option-pricing factors. Traders can buy options for directional exposure, sell options for premium collection, or combine contracts into defined-risk spreads, condors, butterflies, and collars.

Index options should not be confused with ETF options. An index is a benchmark calculation; it does not itself hold assets or trade as a share. An ETF is a fund that owns securities or uses a replication method to track an index and trades on an exchange like a stock. For example, SPX options reference the S&P 500 Index, while SPY options reference shares of the SPDR S&P 500 ETF Trust. This distinction affects settlement, exercise mechanics, contract specifications, tax treatment, and pricing behavior. Many major index options, including standard SPX and NDX contracts, are cash-settled rather than settled through delivery of ETF shares.

Why Traders Use Index Options

Index options provide broad-market or segment-specific exposure through a single contract. Rather than selecting and managing options on dozens of individual stocks, a trader can use an index option to express a view on the large-cap market, technology-heavy growth stocks, small-cap equities, or another defined benchmark. This can simplify automated strategy design because the system monitors one underlying index, one volatility surface, and a standardized set of expirations and strikes. If you are new to systematic execution, our automated trading beginners guide covers the core concepts before you connect live orders.

• Broad-market exposure: SPX options provide exposure to the aggregate behavior of large-cap U.S. equities rather than company-specific earnings or corporate-event risk.
• Sector-weighted exposure: NDX options offer concentrated exposure to the Nasdaq-100, which has substantial technology and growth-stock weightings.
• Portfolio hedging: A trader concerned about a broad market pullback may evaluate SPX put options or put spreads instead of purchasing puts on every stock held in a diversified portfolio.
• Income strategies: Systematic traders may sell defined-risk credit spreads, iron condors, or butterfly spreads when implied volatility and expected index movement support the setup.
• Defined-risk directional trades: Debit spreads can express bullish or bearish views while capping maximum loss at the premium paid.

For automation, position sizing should be based on the index option’s multiplier, strike width, maximum loss, delta exposure, and portfolio-level beta, not simply the number of contracts. TradersPost supports automatic position size calculation so orders can be scaled to a defined risk budget rather than a fixed contract count. A single index contract can represent meaningful notional exposure across many stocks. Short-premium positions, uncovered options, and highly leveraged near-expiration trades can produce substantial losses, particularly during volatility shocks or gap moves. Automated entry rules should therefore be paired with hard risk limits, buying-power checks, spread-width controls, and exit logic that accounts for both price movement and changes in implied volatility.

The Main Index Options: SPX, NDX, RUT, and XSP

SPX Options: S&P 500 Index Exposure

SPX options track the S&P 500 Index and are a primary vehicle for obtaining broad U.S. large-cap equity exposure. Because the index represents 500 leading U.S. companies across multiple sectors, SPX is commonly used for market-direction trades, portfolio hedges, volatility strategies, and defined-risk spreads.

SPX is generally a large-notional product, so contract sizing must be calculated before an order is automated. With an index level near 5,000 and a 100 multiplier, one SPX contract represents roughly $500,000 of index notional before delta is applied.¹ A 25-delta put, for example, has materially less directional exposure than a 100-delta equivalent position, but its premium, gamma, and vega risk can still be substantial.

Traders should distinguish standard SPX expiration conventions from SPXW weekly options. Standard SPX series have historically used different expiration and settlement conventions than PM-settled SPXW series. An automated strategy should never infer settlement mechanics solely from the root symbol or day of week. Verify the precise series, settlement type, last trading date, exercise-settlement value, and expiration details in the current Cboe product documentation. Cboe is the primary source for SPX contract specifications.

NDX Options: Nasdaq-100 Exposure

NDX options track the Nasdaq-100 Index, which is widely used to express views on large, non-financial Nasdaq-listed companies. NDX options are European-style, cash-settled, and use a $100 multiplier.² The index has meaningful exposure to technology, communications, consumer discretionary, semiconductor, and other growth-oriented businesses, but it is not exclusively a technology index.

Relative to SPX, NDX can have greater concentration in its largest constituents and growth-stock sectors. That concentration can produce different volatility behavior, sharper reactions to earnings and rate expectations, and more pronounced factor exposure than a broader market index. For example, a strategy short NDX put premium may face different drawdown dynamics from an otherwise similar SPX strategy during a growth-stock selloff.

Automation should retrieve the current option chain rather than assume every broker supports the same NDX expirations or strike coverage. Check the exchange’s current contract specifications and confirm symbol mapping, available expirations, multiplier, settlement terms, and broker-level chain availability before deployment.

RUT Options: Russell 2000 Exposure

RUT options track the Russell 2000 Index, a widely followed benchmark for U.S. small-cap equities. Like SPX and NDX, RUT options are European-style, cash-settled, and carry a $100 multiplier.³ Common uses include taking small-cap directional views, diversifying concentrated large-cap exposure, and hedging portfolios with meaningful small-cap allocations.

RUT behavior can differ materially from SPX and NDX because small-cap companies tend to have different economic sensitivity, financing needs, interest-rate sensitivity, and sector composition. A trader hedging a small-cap portfolio with SPX puts may therefore retain meaningful basis risk. Automated hedge models should test RUT-specific beta, correlation stability, and drawdown behavior rather than use large-cap assumptions by default.

XSP Options: Mini-SPX Exposure

XSP is designed to provide S&P 500 Index exposure at approximately one-tenth the notional value of SPX; the Mini-SPX Index is based on 1/10th the value of the S&P 500 Index and its options use the same $100 multiplier.⁴ This makes XSP useful when standard SPX contracts are too large for the desired risk budget or when a strategy requires more granular position sizing.

• If SPX is near 5,000, an SPX multiplier of 100 implies approximately $500,000 of index notional per contract.
• If XSP is near 500, an XSP contract represents approximately $50,000 of index notional before option delta is considered.

For automated traders, XSP can allow closer alignment between target hedge notional and executable contract count. Verify exact product specifications, symbols, expirations, liquidity, and settlement terms through Cboe and the trader’s broker before sending live orders.

How Index Options Work: Cash Settlement and Exercise

Cash-Settled Contracts Explained

Many broad-based index options are cash settled, meaning no shares change hands when an option is exercised or expires in the money. This is the standard structure for major products such as Cboe SPX, XSP, and RUT options.⁵ Instead of delivering an index’s component stocks, the clearing process credits or debits cash equal to the option’s intrinsic value at the applicable final settlement value.

For example, assume a trader owns one 5,000-strike index call and the final settlement value is 5,025. The call has 25 index points of intrinsic value. With a 100 multiplier, the cash settlement amount is $2,500:

(5,025 − 5,000) × 100 = $2,500

This amount is before commissions, exchange and clearing fees, taxes where applicable, and any offsets from other positions. A short call at the same strike would have the corresponding cash debit. Settlement calculations, exercise processing, and the timing of cash movement depend on the specific product and expiration series. An automated strategy should not assume that every index option uses the same settlement calendar or final-value methodology.

European-Style Exercise and No Early Assignment

Many index options use European-style exercise, which generally permits exercise only at expiration. This differs from American-style equity options, which can be exercised by the holder on any business day before expiration.

The practical implication for option writers is important: a short European-style index option is not subject to early assignment before expiration. SPX/SPXW options generally may be exercised only on the expiration date, so a trader short an SPX option does not face the possibility of being assigned because of a dividend, a deep in-the-money position, or another holder’s discretionary early-exercise decision during the life of the contract.⁶

That feature does not eliminate risk. A short option can still finish in the money at expiration, and traders remain exposed to market gaps, volatility changes, adverse settlement values, and the risk that a position crosses a strike near the final calculation. Confirm the exercise style for the exact index option product and expiration series being traded; product families can contain different conventions or contract specifications.

AM-Settled Versus PM-Settled Expirations

Index-option settlement may be based on either an AM settlement value or a PM settlement value. AM-settled series commonly use a special opening settlement value calculated from opening prices of the index components. PM-settled series generally use a closing or end-of-day settlement value. For SPX, the standard (third-Friday) series exercise-settlement value is calculated from the opening prices of the component stocks, while SPXW weekly and end-of-month series use the closing prices on the expiration day.⁷

AM settlement creates a distinct operational risk: the final settlement value can differ materially from the prior day’s index close because component stocks may open at different prices, at different times, or with elevated volatility. A position that appears safely out of the money at Thursday’s close can settle in the money based on Friday morning opening prices.

SPX and SPXW are a useful example topic: SPX monthly and SPXW weekly conventions have historically differed, but traders should consult current Cboe contract specifications rather than rely on naming assumptions. Before entering any automated index-options trade, validate:

• Last trading day for the exact expiration series
• Exercise style (European or American)
• Settlement type (AM or PM)
• Final settlement method and calculation source
• Exact expiration series, including weekly, monthly, end-of-month, or other designated contracts

Index Option Contract Size and Notional Exposure

Understanding the 100 Multiplier

Most broad-based U.S. index options are quoted in index points and use a 100 contract multiplier. The cash premium for one contract is therefore:

Option premium in index points × 100 = dollar premium per contract

An option quoted at 12.50 costs approximately $1,250 per contract, before commissions, exchange fees, and any bid-ask execution difference. A trader buying three contracts at 12.50 would pay approximately $3,750 in option premium.

Premium is not the same as total index notional exposure. A simple reference notional for an index option is index level × 100, but an option’s effective directional exposure is better approximated by its delta-adjusted notional:

Index level × 100 × option delta

For example, if an index is at 5,000 and a call has a 0.40 delta, one contract has roughly $200,000 of delta-adjusted directional exposure (5,000 × 100 × 0.40). Delta changes as the index moves, and sensitivity is also affected by strike, time to expiration, and implied volatility. Automated strategies should calculate premium, Greeks, and scenario P&L separately rather than treating the debit paid as the strategy’s market exposure.

Comparing SPX and XSP Sizing

SPX options reference the S&P 500 Index at its full level, while XSP options reference an index designed to be approximately one-tenth the value of SPX. Both generally use a 100 multiplier, but the lower XSP index level produces an approximately one-tenth economic scale per contract.

This difference materially affects capital use, profit-and-loss variability, spread width, and position sizing precision. A trader who considers one SPX vertical spread too large may use XSP contracts to express a smaller fraction of the same broad market view. For example, a 10-point-wide SPX defined-risk vertical has a maximum width of $1,000 per spread before premium. A comparably scaled 1-point-wide XSP vertical has a maximum width of $100 per spread before premium. Three XSP spreads can provide roughly 0.3 of the comparable SPX-scale exposure.

• SPX: typically deeper liquidity, more institutional participation, and often tighter markets in actively traded strikes and expirations.
• XSP: smaller position increments, but potentially different liquidity, strike availability, expiration coverage, quoted spreads, and broker support.

Do not assume SPX and XSP are interchangeable in an automated execution model. Validate the option chain, bid-ask width, available strikes, expiration schedule, routing quality, and transaction costs for the specific product. Smaller contracts can improve sizing control while increasing the number of contracts and per-contract fee impact.

Margin, Buying Power, and Defined Risk

A long call or long put has straightforward risk: the premium paid is generally the maximum loss. Short options and multi-leg positions require more careful buying-power analysis. A defined-risk vertical spread, iron condor, or butterfly may have a calculable maximum loss, but margin is not simply the net credit or debit.

For a short vertical spread, maximum loss is generally:

Spread width × 100 − net credit received

A naked short option can carry substantially larger and potentially changing margin requirements because the risk is not capped by a long protective option. Before transmitting an order, calculate maximum loss, breakeven price, worst-case scenario P&L, and the buying-power reduction under the intended order structure.

Broker treatment varies. Options approval levels, naked-option permissions, concentration limits, portfolio margin eligibility, and intraday margin calculations differ by broker. Automation should query current account buying power and validate margin requirements immediately before order submission rather than relying on static estimates.

Index Options vs. ETF Options

The Key Structural Differences

Index options and ETF options can reference similar market exposures while creating materially different trading, exercise, and settlement outcomes. The primary distinction is that broad-based index options such as SPX, NDX, RUT, and XSP are generally cash-settled. If an in-the-money SPX option expires or is exercised, the account receives or pays the cash difference between the strike and the applicable settlement value. No shares change hands.

By contrast, ETF options such as SPY options are generally settled through delivery of ETF shares. One standard SPY option contract represents 100 SPY shares. A trader assigned on a short SPY call can be required to deliver 100 shares per contract; a trader assigned on a short SPY put can be required to purchase 100 shares per contract. That share delivery can create stock positions, buying-power requirements, borrow considerations for short shares, and unintended overnight exposure.

Exercise style is equally important for automated strategies. Many ETF options are American-style, meaning the holder may exercise before expiration. A short SPY call, for example, can face early assignment risk, particularly before an ex-dividend date when the option has little remaining extrinsic value. Broad index options such as SPX and XSP are generally European-style, meaning they can be exercised only at expiration. This removes one major source of path-dependent assignment uncertainty for short-premium systems.

• SPX versus SPY: Both are associated with S&P 500 exposure, but SPX is a cash-settled index option with a much larger notional size, while SPY options involve shares of an ETF.
• XSP versus SPY: XSP is designed at approximately one-tenth the SPX index level and is often compared with SPY because their quoted levels may be similar. However, XSP remains a cash-settled index option, while SPY is an ETF option with share delivery and American-style exercise.

Similar charts, correlated prices, or comparable index tracking do not imply identical option behavior. Pricing, liquidity, bid-ask spreads, exercise rules, settlement values, dividend effects, tax treatment, and expiration conventions can differ substantially.

When an Index Option May Be Preferable

An index option may be preferable when the strategy requires clean cash settlement and defined exercise mechanics. A systematic trader selling SPX iron condors, for example, may prefer European-style exercise because a position cannot be assigned on Tuesday simply because it is deep in the money. The strategy still has market risk and expiration risk, but it does not need an early-assignment workflow or logic for managing an unexpected ETF share position.

Index options can also suit traders seeking broad benchmark exposure without ETF creation, redemption, dividend, or share-delivery mechanics. SPX may fit larger notional requirements, while XSP can provide smaller index-option sizing for strategies that need cash settlement but cannot efficiently use SPX. Specific index products may also offer expiration schedules that better match a model’s holding period, event-risk rules, or intraday hedging process.

For professional and automated traders, European-style products can simplify operational controls: assignment modeling, margin monitoring, portfolio reconciliation, and end-of-day position handling are more deterministic. Broad-based index options are generally treated as Section 1256 contracts, which are marked to market at year-end and taxed under the 60/40 rule (60% long-term, 40% short-term) regardless of holding period, a different treatment than most ETF options, subject to the trader’s jurisdiction, account type, and tax advice.⁸

ETF options remain appropriate in many cases. SPY may offer different liquidity at particular strikes or expirations, smaller practical trade increments, broader broker support, and easier integration with share-based hedges. The actionable decision is to compare the exact contract: multiplier, exercise style, settlement method, expiration type, liquidity, margin treatment, and post-expiration workflow, not merely the underlying chart.

Practical Index Options Strategies and Trade Examples

Directional Calls and Puts

Long index options provide directional exposure with a known maximum loss: the premium paid plus transaction costs. A long call expresses a bullish view, while a long put expresses a bearish view or provides downside protection. Because SPX, NDX, RUT, and XSP options are cash-settled, there is no assignment of shares; in-the-money contracts settle to cash based on the applicable settlement value.

For example, a trader expecting a short-term advance in the S&P 500 could buy an XSP call or SPX call with 14 to 30 days to expiration. If XSP is trading near 600, the trader might purchase a 605 call for a preset debit. The automation rule should define the maximum premium at risk, the minimum days to expiration, the target delta, and exit conditions such as a profit target, stop based on premium loss, or time-based exit before expiration.

• Maximum loss: limited to the option premium paid.
• Upside: long calls can benefit from an index rally; long puts can benefit from a decline.
• Key trade-off: options lose value through theta decay, and a decline in implied volatility can reduce option value even when the index moves in the anticipated direction.

Credit Spreads for Defined-Risk Premium Selling

Credit spreads sell an option and buy a farther-out option in the same expiration cycle, creating a defined maximum loss. A put credit spread is generally used when the trader expects the index to remain above a support area. A call credit spread is generally used when the trader expects the index to remain below resistance.

For example, an automated strategy might identify an SPX support zone below the current index level and sell a put spread beneath that area. It could sell a 30-delta put and buy a lower-strike put with a 25-point width. Contract quantity should be calculated from the spread width, the net credit received, the $100 multiplier, and a preset maximum loss limit. For one 25-point-wide SPX spread collected for 5.00 points, maximum risk is approximately $2,000: (25.00 - 5.00) × $100.

Short premium positions can benefit from time decay and declining implied volatility, but losses can accelerate when the index moves sharply toward the short strike or volatility rises. Automated systems should monitor delta, distance to the short strike, remaining buying power, and scheduled exits. Traders must also understand the exact expiration and settlement mechanics of the specific SPX, XSP, NDX, or RUT series held near expiration, including whether settlement is AM- or PM-settled.

Portfolio Hedges With Index Puts

Broad-based index puts can offset part of the downside risk in a diversified equity portfolio. A portfolio hedge is rarely exact: portfolio beta, sector concentration, index composition, option delta, and changing correlations all affect hedge performance.

A practical hedge process is to estimate portfolio market exposure, select the index that most closely matches the portfolio, choose a protection horizon, and size the hedge conservatively. For example, a portfolio heavily correlated with large-cap U.S. equities may use SPX or lower-notional XSP puts. An automation model can estimate beta-adjusted notional exposure, select a target put delta, and rebalance only when portfolio value, beta, or time to expiration moves outside defined thresholds.

Hedges have a cost. Protective puts may expire worthless if equities rise or remain stable, and their value can decline as time passes. That cost is the price of maintaining defined downside protection rather than a prediction that a market decline must occur.

How to Trade Index Options Systematically and Safely

Build a Pre-Trade Index Options Checklist

Every index-options order should pass a product-specific checklist before it reaches the market. Do not treat “SPX,” “NDX,” or “RUT” as interchangeable labels: contract terms, settlement conventions, and available expirations can differ materially.

• Product symbol and index exposure: Confirm whether the trade uses SPX, XSP, RUT, NDX, or another index product. For example, XSP is designed to represent one-tenth of the SPX index level, while SPX contracts carry larger notional exposure.
• Strike, expiration, and contract type: Verify the exact strike and expiration selected by the system. Confirm whether that expiration is a standard monthly or weekly/daily series.
• Settlement and exercise: Confirm whether the specific series is AM- or PM-settled, cash-settled, and European-style or American-style. A generic product summary is not enough; standard and weekly series may have different settlement conventions.
• Multiplier and risk: Confirm the contract multiplier, maximum theoretical loss, defined-risk width where applicable, and buying-power or margin impact.
• Exit plan: Define the profit target, stop-loss or adjustment threshold, time-based exit, and expiration handling before entry.

For example, an automated short vertical spread should calculate worst-case loss as spread width less credit, multiplied by the applicable contract multiplier, then reject the order if that loss exceeds the strategy’s per-trade risk cap. Check current Cboe product pages and your broker’s current disclosures for the exact series rather than relying on a static summary.

Define Automation Rules Before the Alert Fires

A trading alert is not an automation specification. Before connecting a signal to an order-management system, define the exact contract-selection, order-entry, and failure-handling logic. “Sell a call spread when RSI is overbought” is incomplete unless the system can determine precisely which contracts, at what price, under which market conditions, and with what safeguards.

• Underlying symbol mapping: Map the signal source to the broker’s tradable option root, including distinctions such as SPX versus XSP.
• Expiration and strike selection: Specify days-to-expiration ranges, standard versus weekly eligibility, delta targets or fixed strike offsets, minimum spread width, and minimum open interest. TradersPost can select expirations programmatically, see automating options trades with dynamic expirations.
• Order logic: Define order type, initial limit-price calculation, permitted repricing increments, maximum debit or minimum credit, and cancellation timing.
• Session controls: Restrict trading to defined market hours and block entries near settlement, major scheduled events, or illiquid conditions if required.
• Duplicate protection: Use unique signal IDs, position-state checks, and daily quantity limits so repeated alerts cannot create unintended exposure.

Paper trade first, then validate at small size with live quotes, fills, rejected orders, and broker buying-power calculations. Market conditions can change quickly; automated systems require hard risk controls, monitoring, and human oversight.

Use Authoritative Product Specifications

Use primary sources for contract terms. Cboe is a key reference for SPX, XSP, and RUT specifications, including multipliers, settlement procedures, exercise style, and listed expiration schedules. For NDX contract details, consult Nasdaq’s official resources or your broker’s current product documentation, as applicable.

Review the Options Disclosure Document before trading. Options involve risk and are not suitable for all investors. Tax treatment, margin requirements, and suitability depend on individual circumstances; consult a qualified tax or financial professional for personal guidance.

Frequently Asked Questions

Are index options cash settled?

Many broad-based index options are cash settled, meaning any in-the-money value is paid or charged in cash rather than settled through the delivery of shares. However, settlement mechanics can vary by product, exchange, and expiration series. Always review the exact contract specifications with your broker and the relevant exchange before trading. Cboe publishes official product details for widely traded index options such as SPX, XSP, and RUT.

Can index options be assigned early?

European-style index options generally cannot be exercised before expiration, so traders holding short positions do not face early assignment. This is a key difference from many American-style equity and ETF options. However, European exercise style does not remove expiration risk: an in-the-money position may still result in cash settlement at expiration. Verify the exercise style for the specific index option contract before placing a trade.

What is the difference between SPX and XSP options?

Both SPX and XSP options provide exposure tied to the S&P 500 Index, but XSP is designed at approximately one-tenth the scale of SPX. That smaller notional value can give some traders more flexibility when sizing positions or managing risk. Before choosing between them, compare available expirations, bid-ask spreads, liquidity, contract specifications, and whether your broker supports the product and order types you need.

What is the difference between index options and ETF options?

Index options are based on the value of an index, while ETF options are based on shares of a tradable exchange-traded fund. Many major index options are cash settled and European style, whereas ETF options are often physically settled and American style. As a result, assignment risk, settlement procedures, tax treatment, liquidity, contract sizing, and trading behavior can differ significantly between the two products.

Can I automate index options trading with TradersPost?

TradersPost can connect TradingView alerts to supported brokers for automated trading workflows; see how to automate options trading on TradingView with TradersPost. Whether you can automate a specific index option, strategy type, or multi-leg order depends on current broker integrations, account permissions, and supported order features. Before trading live, thoroughly test your workflow and use safeguards such as position-size limits, risk controls, duplicate-alert prevention, and clear rules for handling failed or delayed orders.

Conclusion

Index options offer a focused way to express broad market views without selecting individual stocks, but SPX, NDX, RUT, and XSP are not interchangeable. Contract size, underlying exposure, settlement style, tax treatment, liquidity, and trading hours can materially affect both risk and execution. Match the index to your thesis and account size, then define position sizing, exits, and alert conditions before placing a trade.

To make that process more consistent, explore TradersPost, connect a supported broker, and test your TradingView alert workflow in a simulated or small-size environment before deploying live index options trades. A disciplined workflow can help turn a market idea into a repeatable plan, start building and validating yours today.

References

¹ Cboe: S&P 500 Index (SPX) Options Product Specifications
² Nasdaq: Nasdaq-100 Index Options: XND and NDX
³ Cboe: Russell 2000 Index (RUT) Options Product Specifications
⁴ Cboe: Mini-SPX Index (XSP) Options Product Specifications
⁵ Cboe: Index Options Benefits: Cash Settlement
⁶ Cboe: SPX Options Specifications (Exercise Style)
⁷ Cboe: SPX Options Specifications (Settlement Value)
⁸ IRS: About Form 6781, Gains and Losses From Section 1256 Contracts and Straddles