Thanks Vega,
From the ISE -- which says that these rules are similar to other exchanges (easiest info I could find):
The maximum spread for normal equity options may be no more than:
⢠¼ of a point where the bid is less that $2;
⢠3/8 of a point where the bid is at least $2 but does not exceed $5;
⢠½ of a point where the bid is more than $5 but does not exceed $10;
⢠¾ of a point where the bid is more than $10 but does not exceed $20; and
⢠$1 when the bid is $20 or greater.
The Bid/Ask differentials stated above shall not apply to in-the-money optionsseries where the underlying securities market is wider than the differentials setforth above. For these series, the Bid/Ask differential may be as wide as thequotation on the primary market of the underlying security.
Additionally, the ISE has established the following policy with regard to Bid/Askspread differentials in LEAPS options:
⢠For LEAPS options with one year or less to expiration, the maximumBid/Ask spread differential shall be the same as provided for standard equityoptions.
⢠For LEAPS options with more than one year to expiration, the maximumBid/Ask spread differential shall be no greater than twice the maximumprovided for standard equity options, except that options priced at $1 or lessmay be no wider than 3/8 of a point.
⢠In no event may the Bid/Ask differential for a LEAPS option be greater than$1 wide.