However, it's what these things could mean for already sluggish growth that is the real worry.
The US is still chugging along nicely, but numerous companies have reported a softening outlook and the housing market has lost a bit of steam as higher mortgage rates bite.
Last week Europe reported the slowest growth in business activity in more than four years, as job creation slipped to a two-year low and business optimism also declined.
Meanwhile, Japan has seen exports decline by the most in over two years, while business confidence has been declining for several months.
China, the world's second largest economy after the US, is probably the biggest area of concern. Steady Chinese growth, much of it driven by government stimulus, has supported global growth for some time now.
However, that backstop might no longer be there during the next year or two, at least not to the same degree. Industrial production growth fell in November to the slowest in almost three years, while retail sales growth also fell amidst weak vehicle sales.
Owning a share means you have a small stake in a bigger business, one which sells products or services to customers and hopefully has some profits left to share with you after the costs of delivering those are deducted.
The price of that share simply reflects what the market believes all those future revenues and profits are worth today. If the outlook for economic growth suddenly looks less buoyant, so do those future revenue expectations.
Investors begin to factor in less products being sold, falling margins and lower profits. As this picture starts to look less rosy, the share price adjusts accordingly. Hence the sell-off we are in the middle of.
It's difficult to see what might turn the negative sentiment around. Rather than the US Fed telling us they'll tread more carefully, or Trump tweeting something positive about trade, what we really need is evidence that global economic growth is stabilising.
• Mark Lister is head of private wealth research at Craigs Investment Partners.
