The New York Stock Exchange, After Technical Struggles, Has Reopened

It's been a weird day for high-profile tech glitches.

In what has been an unusual day for high-profile tech glitches, trading on the New York Stock Exchange was suspended for more than three hours before reopening Wednesday afternoon.

Activity was initially halted because it was "experiencing a technical issue that we're working to resolve as quickly as possible." In the hour before the NYSE began operating again, its president, Thomas Farley, told CNBC that it would open between 2:45 p.m. and 3 p.m., before its daily 4 p.m. close. It officially reopened shortly after 3:10 p.m.

NYSE's morning announcement of the suspension came several hours after United Airlines temporarily grounded its planes due to an "automation issue." There's no indication right now that the two issues were related.

Early Wednesday afternoon, the NYSE said on Twitter that the problem is "an internal technical issue and is not the result of a cyber breach." But there was some concern on the Hill about the glitch's origins. Florida GOP Sen. Bill Nelson told reporters after news of the suspension broke that "it has all the appearances of a cyberattack." He later elaborated on Twitter:

Senate Intelligence Committee Chairman Richard Burr didn't see cause for alarm. "From everything I can gather in a short period of time, there's nobody in the intelligence community that believes a cyberattack had anything to do with it. Just coincidence," the North Carolina Republican said.

A White House official said the president had been briefed on the situation at the NYSE, and officials from the White House and Treasury Department have been keeping an eye on it as it developed. White House press secretary Josh Earnest said during his Wednesday briefing that the president was told that "at this point, there is no indication that malicious actors were involved in these technology issues."

At the start of a planned Wednesday speech on cyberattacks, Homeland Security Secretary Jeh Johnson said the United and NYSE hitches had nothing to do with a "nefarious actor."

According to the exchange's market status webpage, trading was suspended for more than an hour in the morning after a hitch was resolved.

United had experienced "a network connectivity issue" Wednesday, but resolved the problem by about 10 a.m. For a brief period in the morning, The Wall Street Journal's homepage was also down, driving as-yet-unsubstantiated suspicion that the three technical issues are linked. The page's functionality was restored shortly before 1 p.m.

Securities and Exchange Commission Chair Mary Jo White said Wednesday afternoon that her organization was "closely monitoring" the NYSE's outage. A New York Times report indicated that NYSE officials told traders that the technical issue "was related to updated software that was rolled out before markets opened on Wednesday."

Rebecca Nelson contributed to this article