SPX vs SPY Options: Index Options vs ETF Options, and XSP

Reviewed by Leon Moyer - Published October 9, 2026 - Last reviewed October 9, 2026

SPX options are options on the S&P 500 Index itself: cash-settled, European-style, and sized at the full index level times $100. SPY options are options on an exchange-traded fund (ETF) that holds the index's stocks: American-style, settled by delivering 100 ETF shares, and about one tenth the size. XSP, the Mini-SPX option, sits between them, with SPX's cash settlement and European exercise at roughly SPY's size.

All three move with the same 500 stocks, so the choice is not about direction. It is about how big the contract is, what happens if you hold it to expiration, and whether you can be assigned early.

What is the difference between SPX and SPY options?

An option gives its buyer a right: a call to buy, a put to sell, at a fixed strike price until expiration. With SPY, that right is about real ETF shares. With SPX and XSP, there is nothing to deliver, so the right is settled in cash. The Options Industry Council puts it simply: index options are traditionally cash-settled, while standard equity options are physically settled.

Sources: Cboe's SPX specifications, XSP specifications and XSP exercise style page, which notes that all equity and ETF options are American-style.

How big is one SPX, XSP or SPY contract?

Contract size, or notional value, is the value of the index or shares one contract controls. With the S&P 500 at a hypothetical 6,000:

• SPX: 6,000 x $100 = $600,000 per contract.
• XSP: Cboe defines XSP as one tenth of the index, so 600 x $100 = $60,000.
• SPY: the ETF trades near one tenth of the index, but not exactly, because it is a fund with its own price. At a hypothetical $598, one contract covers 100 shares, $59,800.

That size difference is the main reason many traders who like SPX's rules use XSP: the same trade at one tenth of the dollar risk.

What happens to SPX, XSP and SPY options at expiration?

This is where the difference becomes concrete. Cboe's XSP cash settlement page walks through a 600 call that finishes at 605:

• XSP 600 call: it settles at 5.00 points in the money. You are credited (605 - 600) x $100 = $500 in cash and the position is gone.
• SPY 600 call: it is exercised into 100 shares at $600. You now own 100 SPY shares and must pay $60,000 for them, and you hold them, with their market risk, until you sell. If you do not have the cash or margin, your broker may act on your account.

The same logic applies to puts: an in-the-money SPY put sells 100 shares you may not own, leaving you short the ETF, while an XSP or SPX put simply pays cash.

Why can SPY options be assigned early, but not SPX?

SPY options are American-style, so the holder can exercise on any business day and the seller can be assigned at any time. Cboe's exercise style page explains the classic case: if a call is in the money before an ex-dividend date and the dividend is larger than its remaining time value, the holder may exercise early to collect the dividend, and the seller is assigned. SPY pays dividends, so a seller of in-the-money SPY calls can face this.

SPX and XSP are European-style, so assignment can only happen at expiration. European vs American Options covers the details.

Do SPX and SPY options have different tax treatment?

They can. Cboe's SPX Weeklys page and XSP exercise style page note that under Section 1256 of the U.S. tax code, gains and losses on certain exchange-traded options, naming SPX and XSP respectively, may be taxed as 60% long-term and 40% short-term, provided the investor and the strategy meet the code's criteria. IRS Publication 550 lists broad-based stock index options among the nonequity options that rule covers. SPY options are options on an ETF, and their treatment can differ. Exceptions apply. Course 4's Tax Treatment of Options module covers the basics, and a tax professional can tell you how the rules apply to you.

For the long XSP call: the maximum loss is the $694 premium. The maximum profit is unlimited in theory, because the cash payout grows as the index rises. The break-even is the strike plus the premium, 616.94.

Which should you trade: SPX, XSP or SPY?

• SPX fits traders who want cash settlement, no early assignment and a choice of AM or PM expirations, and who can carry a contract worth about $600,000 at a 6,000 index level.
• XSP keeps SPX's cash settlement and European style at about SPY's size. Check its bid-ask spread and open interest before trading, as you would for any option.
• SPY is familiar, very actively traded, and delivers shares, which some traders want, for example when selling covered calls on SPY shares they already own.

Whichever you use, a bought option risks only its premium, while an uncovered short call on any of the three carries unlimited risk.