The news that US President Donald Trump tested positive for Covid-19 brought turmoil to the markets, but they are now beginning to climb again on news his health is improving.
However, with investors already braced for post-election turbulence, the situation adds a further degree of uncertainty.
With many commentators agreed we are about to enter a period of high volatility, it looks as if the markets will remain on edge for the foreseeable future.
"Donald Trump catching coronavirus has put the markets in a mild state of disarray," said Russ Mould, investment director at AJ Bell.
"First, the President of the United States becoming ill creates a sense of instability for markets in general.
"Second, it raises the question of how the presidential election will play out - has Joe Biden also been affected, will Trump be well enough to continue the debating while self-isolating, and will the elections be postponed?"
Trump's diagnosis has added a fresh dose of uncertainty to the market, boosting volatility.
"The bottom line is that the US elections have many moving parts and will be a sure source of market volatility over the next month or two," said Rupert Thompson, chief investment officer at Kingswood.
"That said, we are not expecting a repeat of anything like the turbulence we saw earlier in the year. At the end of the day, the lesson from history is that Federal Reserve policy is generally much more important for markets than Government policy - and the Fed is a centre of stability at the moment with policy firmly on hold."
Paul O'Connor, head of multi-asset at Janus Henderson, said that while there are questions about what happens if Trump's health deteriorates, the markets are more focused on the outlook for fiscal stimulus for now.
"Another potential interpretation for today's recovery in risk assets is that investors believe that the president's illness will improve the likelihood of compromise being reached on the contentious US fiscal stimulus package," he said.
"Some might take encouragement from Donald Trump's weekend tweet urging negotiators to 'work together' on this. However, the big divide here is not between the Democrats and the president, but between the Democrats and congressional Republicans.
"A decisive breakthrough before the November election would be a surprise to us and a positive surprise for investor risk sentiment."
Asset manager Nuveen said that while the news added to uncertainty, investment implications will remain limited.
"In light of the additional uncertainty we are faced with today, we do not suggest investors make significant changes to their asset allocations or overall wealth strategies in advance of or following the November elections."