Update: Sentiment is taking a beating after the news that The FBI is reopening the case...

Update:

As CNBC adds, Donald Trump seized on the news Friday that the FBI is probing new emails related to Hillary Clinton's private server, contending that she threatens United States security and cannot be trusted in the White House. "I have great respect for the fact that the FBI and Department of Justice are now willing to have the courage to right the horrible mistake that they made," Trump said at a rally in New Hampshire. "This was a grave miscarriage of justice that the American people fully understood and is about to be corrected."

"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation. I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation," Comey wrote.

As FBI reopens inquiry into @HillaryClinton emails, @realDonaldTrump says it's a scandal worse than Watergate https://t.co/XNZcYcbbYU pic.twitter.com/9V4G699fbQ — BBC Breaking News (@BBCBreaking) October 28, 2016

"Although the FBI cannot yet assess whether or not this material may be significant, and I cannot predict how long it will take us to complete this additional work, I believe it is important to update your Committees about our efforts in light of my previous testimony," he concluded.

Trump claimed that "Clinton's corruption is on a scale we have never seen before."

Update:

More details from CNN which writes that after recommending this year that the Department of Justice not press charges against the Secretary of State, Comey said in the letter to eight congressional committee chairman that "recent developments" urged him to take another look.

"In connection with an unrelated case, the FBI has learned of the existence of emails that appear pertinent to the investigation," Comey wrote the chairmen. "I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation."

Comey said that he was not sure how long the additional review would take and said the FBI "cannot yet assess whether or not this material may be significant."

Law enforcement sources say the newly discovered emails are not related to WikiLeaks or the Clinton Foundation. They would not describe in further detail the content of the emails. It's also unclear whether the emails in question are from Clinton herself.

Clinton's campaign learned of the news while they were aboard a flight to Iowa. "We're learning about this just like you all are," a Clinton aide told CNN.

The surprising news jolts a presidential race that had largely settled as Republican presidential nominee Donald Trump struggled in national and key battleground polls. Now, Clinton will be placed back on the defensive and forced to confront yet again questions about her trustworthiness.

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As we detailed earlier, in a stunning development moments ago Jason Chaffetz tweeted that the FBI's probe into Hillary Clinton emails has been reopened: saying that "The FBI has learned of the existence of emails that appear to be pertinent to the investigation."

FBI Dir just informed me, "The FBI has learned of the existence of emails that appear to be pertinent to the investigation." Case reopened — Jason Chaffetz (@jasoninthehouse) October 28, 2016

After being briefed by his investigative team, Comey "agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to asses their importance to our investigation." Comey said he could not predict how long it would take the bureau to assess whether the new emails are "significant."

Moments later, NBC News reported that the agency was reopening the investigation and shared a letter from FBI director James Comey informing key lawmakers of the investigation.. .

“In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation,” Comey wrote. “I am writing to inform you that the investigative team briefed me on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information,” Comey wrote

The full letter to members of Congress, in which FBI director James Comey said the agency had "learned of the existence of emails that appear to be pertinent to the investigation" in connection with an unrelated case, is shown below.

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While we seek more information, the Mexian Peso has just crashed in reaction to the news.

And stocks have erased any gains for the day.

And Bonds & Bullion safe havens are bid for now.

Charts: Bloomberg