Index options fees: the same S&P exposure costs $1.72 in SPX and $11.90 in XSP, because every fee is per contract

SPX, XSP and Nanos track one index at one tenth and one thousandth of the size. Fees are charged per contract, not per dollar of exposure, so the small contracts cost multiples of the big one. IBKR's own all-in figures put Nanos between fifty and one hundred and seventy times the cost of SPX per dollar covered.

Last verified 24 September 2026 · how we check

Cboe lists three sizes of S&P 500 index option. They track the same index, settle in cash and expire on overlapping schedules. The only real difference is size, and every fee attached to them is charged per contract rather than per dollar of exposure.

That is the whole problem with the small ones.

Three contracts, one index

From IBKR’s own product table, at an SPX index value of 4100:

Ten XSP contracts hold roughly the exposure of one SPX contract. A thousand Nanos do.

IBKR publishes the all-in rate, so the arithmetic is easy

The same page gives IBKR’s commissions per contract, all in, depending on monthly volume:

Read the right-hand column. Nanos cost between fifty and one hundred and seventy times what SPX costs per dollar of exposure, depending which end of each range you compare, and XSP costs about four times SPX. Per contract they look cheaper. Per unit of the thing you are buying, they are not.

That is not a criticism of the small contracts. A trader who wants $410 of exposure cannot buy it in SPX at all. The mistake is treating the per-contract price as the comparison.

At tastytrade, the gap is wider, and the cap does not help

tastytrade charges $1 a contract to open and nothing to close, capped at $10 per leg, plus $0.10 clearing per contract. But its schedule states that broad-based index options “are excluded from the capped commission offer”, and adds a proprietary index fee per contract:

Open one SPX contract, and open the same exposure in ten XSP contracts, and count what the schedule charges on the opening trade:

$1.72 against $11.90 for the same position. Every line except the index fee multiplies by ten, and the $10 leg cap that would have held the commission down does not apply to index options. We set out the rest of that schedule in tastytrade fees.

Webull charges for index options and nothing for the rest

Webull’s fee schedule has no commission on US-listed stocks, ETFs or ordinary options, and one exception: index options.

At $0.50 a contract, one SPX costs $0.50 and ten XSP cost $5.00, before regulatory fees. The ratio is the same ten to one, from a broker whose headline is zero commission. The only options product Webull charges a commission on is the one that tracks an index.

Schwab and IBKR name the fee without pricing it

Schwab’s pricing page charges $0.65 a contract on options and notes separately that an exchange may charge a proprietary index option fee on products that trade only there, naming SPX, OEX and VIX. It does not give the amount. Neither does IBKR’s options commissions page, which carries no separate index rate at all; its exchange and regulatory fees sit on top of the same per-contract schedule we costed in what it costs to trade options.

One programme is worth knowing before assuming the published rate is the only one available. IBKR’s page notes that Cboe runs a Frequent Trader scheme with rebates on certain proprietary products, that clients must apply to the exchange themselves, and that IBKR then has to be notified by email so orders are tagged correctly.

Why the small contracts still exist

Position sizing. At an index near 4100, one SPX contract is about $410,000 of notional exposure and an at-the-money two-day option costs around $3,000 in premium on IBKR’s own example. The same trade in XSP costs about $300, and in Nanos about $3.

So the choice is not which contract is cheaper. It is whether the exposure you want fits in a $410,000 increment. If it does, the big contract is several times cheaper in fees. If it does not, the fee premium on the small one is the price of being able to place the trade at all.

What to do with this

Convert the fee to a per-notional figure before comparing. Divide the per-contract cost by the contract’s notional. It is the only comparison that holds across sizes.

Check whether a commission cap excludes index options. At tastytrade it does, and that turns a ten-lot into a full-price order.

Count the index fee on both legs. It is charged per contract on the way in and, where the schedule applies it to all trades, on the way out.

Do not assume a zero-commission broker is zero here. Index options are the exception on Webull’s schedule.

What we checked, and what we didn’t

Contract multipliers, notional sizes, premium examples and IBKR’s all-in commission ranges were read from IBKR’s Cboe SPX page on 24 September 2026, with the notional figures stated there at an index value of 4100. tastytrade’s commissions, clearing fee, cap exclusion and index fee table come from its fee schedule last updated 30 July 2026, and Webull’s index option pricing from its fee schedule, both read the same day. The per-notional figures and the SPX-versus-XSP totals are our arithmetic.

The index level of 4100 is IBKR’s illustration, not today’s market; at a different level every notional figure and every per-notional cost moves with it, though the ratios between the three contracts do not. We have not reproduced exchange or regulatory fee amounts at Schwab or IBKR, which neither publishes on the pages cited, and we hold no account at any of these brokers.

Sources

• Interactive Brokers: Cboe SPX, XSP and Nanos, contract table and all-in commissions
• tastytrade: commissions and fees schedule, last updated 30 July 2026
• Webull: fee schedule, index options pricing
• Charles Schwab: pricing and account fees