“Sell in May and Go Away” is probably the best known stock market adage.

But how did it come about and is it worth considering in modern times?

The second half of this saying is “Buy again St Leger Day”. What’s this all about?

It could well be that the saying emanates from the first half of the 20th Century when the majority of shares were owned by wealthy private individuals and family trusts.

At this time, the social ‘season’ played an important part in the life of the wealthy landed gentry and in May their London homes would be closed and the family would move to the country to enjoy the season of sporting and social events.

With communications far less efficient than today, it would make sense to sell your holdings so that you could enjoy a stress free summer whilst activity in the city declined with most of the big players away from their desks.

It is still true today that the city becomes quiet in the summer months as attention switches to Lord’s, Wimbledon, Ascot and Cowes but with a more global stockmarket family and 24 hour communication the summer season has less effect than previously. St Leger Day is the date of the famous St Leger horse race run at Doncaster in mid-September for over 230 years and traditionally marked the end of the summer season. Hence at this point city life would stir again and buying from your broker would be recommended.

But does following this tactic actually work?

The stockmarket historian David Schwartz notes that from 1920 to 1970 UK shares rose 65 per cent of the time in the period between November and April versus 58 per cent of the time between May and October.

Not a huge difference and with the difficulty of getting timing exactly right, and the additional costs of dealing, it would rarely benefit to make a decision in favour of ignoring the stock market in the summer months based on these figures.