Stocktake: Is a big sell-off in store?

February was a mixed month for stock markets. The Bloomberg World index began the month with 11 consecutive daily gains, notes Bespoke Investments, before falling in eight out of nine trading days as the month progressed.

The rollercoaster ride has continued in March, which began with the S&P 500 gaining 2.4 per cent – its biggest one-day gain in nine months – before tumbling in the following days.

Is this a run-of-the-mill pullback in a bull market or the beginnings of an unnerving sell-off? Who knows, although investors shouldn’t panic if stocks do sell off. After all, sell-offs are perfectly normal. Since 1980 the S&P 500 has suffered an average intra-year decline of 14.3 per cent, according to JP Morgan data, even though stocks gained in 31 of those 41 years.

That aside, history indicates any sell-off is unlikely to be protracted. LPL Research's Ryan Detrick found 15 instances since 2009 where the S&P 500 registered a one-day gain of at least 2.3 per cent while above its 200-day average. Six months later, stocks were higher every single time, averaging gains of 11.8 per cent.