Anonymous may have been involved in the problems that have crippled the New York Stock Exchange, according to a tweet sent by the group.

"Wonder if tomorrow is going to be bad for Wall Street...." one of the group's most popular accounts tweeted. "We can only hope."

Authorities have so far denied that there is any sign of a hack. But YourAnonNews sent the tweet around midnight local time, before the problems were known and when the exchange was closed.

While many accounts associate themselves with the group, a few have formed that send out detailed information about the attacks and seem to have inside information on the group's workings.

YourAnonNews is one of those pages, having been central in previous operations by the group. It describes itself as a "Signal boost for Anonymous operations, resistance movements, & journalism," and has nearly 1.5-million followers.