The Dow Jones had been leaking all day on uncertainty over the health care vote - then rallied when that uncertainty ended.

John Mervin, BBC business, New York, writes:

In the event, Donald Trump and the GOP's failure to repeal Obamacare, doesn't seem to have bothered investors too much. The Dow Jones Industrial Average fell 60 points on Friday, pulling back some of its earlier losses as news came out that the bill was being pulled.

More than events themselves, it's unexpected events that tend to spook financial markets, hence the lack of a freak-out at this undeniably big moment for the Trump administration.

It's also true that markets have always been more concerned with other parts of President Trump's economic agenda, namely his plans to cut regulations and taxes. Some people clearly think that repealing Obamacare was an unhelpful distraction from that, and now it's apparently not happening, the thinking goes, the Republicans can get on with plans they can carry out. Indeed some feel this quick failure is preferable to a bill passing the House only to get bogged down in further months of recrimination and bad PR in the Senate.

But that all presupposes tax cuts will now be easy. What if they're not? What if the failure of healthcare bill is simply the first part of a wider unravelling of Republican plans? In that case, the investor freak-out about a failure of Trump's economic agenda hasn't been avoided. It's just been delayed.