What causes intra-week regularities in stock returns? Some evidence from the UK

The calendar anomaly associated with negative stock returns over the weekend is investigated. It is argued that such effects may be caused by a number of institutional features. Using Datastream's daily stock returns index for the UK over the period 1980-1993, it is shown that after allowing for three institutional factors there is no residual weekend anomaly to be explained. These factors are: (i) financing discontinuities associated with the account settlement period; (ii) the relative scarcity of funds while finance is held in banks suspense and transmission accounts on Settlement Day; and (iii) firms reluctance to hold money during non-trading periods.