Since 1986, when the Stockholm Stock Exchange's OMXS30 index of the largest stocks made its debut, the average return in September has been minus 1.2 percent. Only August shows worse figures, at minus 1.38 percent, according to Nicklas Andersson's review of stock market statistics.
But that effect has waned over the past ten years, he says, noting that seven of the last ten Septembers have ended positively.
Winter sports
It is often said that the stock market is a winter sport. This is traditionally when stock prices rise. August and September are often characterised by a period when stock market speculators return from the summer and reassess the situation, with falling prices as a result.
October has otherwise been given the epithet of horror month.
But when it has been really dark, it usually turns around in October, says Andersson.
Whether September will end in the red again this year is of course impossible to say. But it has started gloomily in the wake of growing concerns about the conflict between the US and Iran. Oil prices are rising again, inflation concerns are increasing and interest rates are rising to their highest levels in many years, which is a bad cocktail for the world's stock markets.
No selection effect
We see that the conflict in the Middle East is escalating. And then we have the American midterm elections in November. That adds extra uncertainty, says Nicklas Andersson, who, however, sees an improved economic situation in Sweden, among others, which counteracts that picture.
This year, September is also an election month in Sweden. But it is difficult to find any direct historical patterns. It is true that there have been large negative numbers on average in September, especially during election years, but this is explained by individual major international events, according to Nicklas Andersson.
Global risk appetite and economic conditions, the American stock market, have a greater impact than the Swedish parliamentary election, he says.
