SPX is the ticker for options on the S&P 500 Index, listed on the Chicago Board Options Exchange (CBOE). The underlying is the S&P 500 Index itself — an index of about 500 large US companies. Buying an SPX option is not buying shares; it is a bet on the level of the index: however many points the index moves, the contract settles by points.
Four verified mechanics
Cash settlement: at expiry, an in-the-money contract settles in cash at (settlement value − strike) × $100. No shares change hands, and exercise never leaves you holding a basket of stocks.
European-style exercise: exercise can only happen at expiration, never early, so a seller faces no early-assignment risk — unlike American-style stock options.
$100 per point: the contract multiplier is $100 per index point. A 1-point move in the index changes one contract’s notional value by $100, and premiums are quoted per point — multiply by 100 for the total price of one contract.
Two settlement times: standard monthly contracts (expiring the third Friday of the month) are AM-settled: they settle on a value computed from expiration-day opening prices, and trading in them stops the day before expiry. Weekly and daily contracts (SPXW, including 0DTE) are PM-settled: they settle on the expiration-day closing index value and can trade until 4:00 p.m. ET that day.
Simulate first, then talk about anything else
This simulator uses CBOE delayed quotes (about 15 minutes delayed), starts with $10,000 virtual cash, charges $0.65 per contract per side, and shows P&L net of fees. Its purpose is to practice order entry, discipline, and review. It is not investment advice and promises no returns.