Four market experts discuss what could come next.
Barry Bannister, head of institutional equity strategy at Stifel, sees this as a computer-driven rotation.
"To an extent it does feel like too much money chasing too few ideas. It's very hard to make that rotation from growth to value, from disinflation to reflation without there being some interruptions in the market. So I think it's just a lot of money, a lot of liquidity, a lot of algorithms that are just saying, 'Well, these didn't go up, let's buy them. The other ones may have went up a lot, let's sell them.' So it's almost like a computer-driven rebalancing."
Stephen Weiss, founder of Short Hills Capital Partners, said investors should assess how much damage was done.
"Greed has a way of just biting you in the a-- at some point, and then you have to decide 'OK, is it a flesh wound or is it drawing real blood?' I think it's more of a flesh wound. I think it's taking some of the weak-handed traders that are coming out, buying stocks like Zoom at the top that are now selling them. We saw it start to unwind [Wednesday] with Apple."
Rob Sechan, managing director at UBS, sees a rotation out of tech.
"There are reasons that the market is selling off. We've seen these tech names perform tremendously well, it looks like they've reached some unsustainable prices. Whether that ends today or tomorrow I don't think anybody knows when that happens, but the risk reward trade-off between growth and value has certainly been pushed to a great divergence level and so we have used the latest moves in markets in tech to take money out of momentum, move money into some of the cyclical laggards."
Jason Snipe of Odyssey Capital Advisors says investors are taking profits after the summer surge.
"I look at this summer, which is historically great, particularly last month which was the best August in decades. I think it's a little bit of rebalancing, I think it's a little bit of profit-taking. I know September is historically a slow month, there won't be a lot of news coming and also preparing for the election."