AM vs PM expiration for index options

[elite1974]

Can someone please explain the ideas and strategies behind choosing an AM vs PM index option expiration?

If I buy an SPX 4000 put, for June 16th.
AM expiration - 68.2 is $6820
PM expiration - 69.1 is $6910

 

[BMK]

The PM expiration options can be traded until 4:15 PM on the day of expiration.

The AM expiration options are weekly--they only expire on Fridays--and they stop trading at the close of the market on Thursday.

 

[elite1974]

so for the AM index option with cash settlement, does it get the price of Thursday close, or the price of Friday open.

 

[BMK]

so for the AM index option with cash settlement, does it get the price of Thursday close, or the price of Friday open.

Friday opening price

https://www.marketdata.app/spx-vs-spxw-options/

 

[FSU]

The PM expiration options can be traded until 4:15 PM on the day of expiration.

The AM expiration options are weekly--they only expire on Fridays--and they stop trading at the close of the market on Thursday.

The AM options are monthly only , not weekly. These expire once a month. They trade on the regular session until 415pm et and continue to trade on the curb session until 5pm et Thursday. They will expire based on Friday mornings opening of the SPX stocks.

The PM options can only be traded until 4pm on expiration (not 415) and expire based on the closing price of the SPX component stocks. Non expiring PM options trade until 415 in the regular session

PM symbol SPXW
AM symbol SPX

 

[BMK]

The AM options are monthly only , not weekly. These expire once a month. They trade on the regular session until 415pm et and continue to trade on the curb session until 5pm et Thursday. They will expire based on Friday mornings opening of the SPX stocks.

The PM options can only be traded until 4pm on expiration (not 415) and expire based on the closing price of the SPX component stocks. Non expiring PM options trade until 415 in the regular session

PM symbol SPXW
AM symbol SPX

I stand corrected on both issues.

 

[stepandfetchit]

FSU's statements are spot on.
The AM SPX were first introduced with the Weeklies being added much later. For a time, the lions share of the trading was only with the AM SPX options. The PM expirations have gained favor and are preferred by most retail traders now. -- The notion that trading ceases on Thursday and the actual settled values unknown until Friday AM makes trading near expiration uncomfortable for many traders. The AM expiration may still have more volume than their weekly counterparts but the spreads seem to be tighter on the weeklies finally!