Why do the quarterly "PM settled" options for the S&P 500 futures have about 1000 points between each strike price?

External question — Personal Finance Stack Exchange Author: 7529 Original post: https://money.stackexchange.com/questions/151395 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I'm looking at the options chain for the S&P 500 futures. Almost every option contract I look at, whether it's a daily option, weekly option, monthly option, or quarterly "AM settled" option has 5 points between each strike price. For example, here is the option contract expiring next Thursday - you can see strike prices 3675, 3680, 3685, 3690, 3695, 3700, 3705, 3710, 3715, 3720: However, every quarterly "PM settled" option I look at has a massive spread between each strike price - about 1000 points between most strikes. For example, here is the option contract expiring tomorrow afternoon - you can see strike prices 100, 200, 1100, 2100, 2200, 3100, 4100, 4200, 5100, 6100, 7100, 8100: The next quarterly "PM settled" option expiring in September has those exact same strike prices. Why would the quarterly "PM settled" options offer so few strike prices, when all the daily, weekly, and monthly options (which are also "PM settled") offer strike prices every 5 points? Having such a massive spread between strike prices eliminates a lot of options strategies for people who want to trade on the day of expiration of the quarterly option (aka quadruple witching).