Weekly Options are one week options. In October, 2005 the Chicago Board Options Exchange introduced four weekly index options.
The four weekly index options are SPX, XSP, OEX, and XEO.
SPX Weekly- represents the S&P 500 index with trading starting every Thursday A.M. and settlement on the following Friday A.M. Therefore the SPX Weekly expires every market's Thursday close.
XSP Weekly- represents the S&P 500 index but at 1/10th the value.
OEX Weekly- represents the S&P 100 index with trading starting every Friday A.M. and settlement on the following Friday P.M. Therefore the OEX Weekly expires every market's Friday close.
XEO Weekly- is identical to the OEX Weekly except XEO can not be exercised until its expiration date while OEX can be exercised before expiration date.
All four weekly index options mentioned are cash-settled options.