This chapter provides an empirical analysis of trading-restricted, business days and trading, non-business days on the Australian Securities Exchange (ASX). Seven days are included in the analysis: the Bank Holiday in NSW (non-business), Labour Day in NSW (non-business), Easter Thursday (early close), Labour Day in Victoria (non-business), Melbourne Cup Day in Melbourne (non-business), the last business day before Christmas (early close) and the last business day of the calendar year (early close). Three indexes provide different daily return measures: the All Ordinaries (market), 1958-2007, the Small Ordinaries (small-cap), 1994-2007; and the ASX100 (large-cap), 1992-2007. The findings indicate return abnormalities on three days when trading and/or business activity is restricted: Melbourne Cup Day, the last business day before Christmas and the last business day of the calendar year.