Previous research has implicitly assumed, or even suggested, that the relat
ionship between option moneyness and liquidity is quadratic with liquidity
maximized for at-the-money options. This study investigated the nature of t
he relationship between moneyness and three liquidity proxies for options o
n the Standard & Poor's (S&P) 100 and S&P 500 indexes. With bid-ask spreads
, volume and time between quotes as liquidity proxies, statistical analysis
rejected the hypothesis of a simple quadratic relationship between moneyne
ss and liquidity in these markets. Although liquidity was maximized near th
e money, liquidity did not decrease symmetrically as option strikes moved d
eeper in the money or deeper out of the money. (C) 2000 John Wiley & Sons,
Inc.