U.S. equity markets will resume trading on Monday, September 17 at the latest, according to a joint press conference between the Securities and Exchange Commission, the New York Stock Exchange and Nasdaq.

U.S. treasury markets will begin trading tomorrow.

Although stocks probably won’t resume trading until Monday, there is a chance the markets will open again on Friday, the markets announced in a joint decision.

The same group of regulators will meet again tomorrow to assess the feasibility of a Friday opening, but for now the group is planning on Monday.

NYSE head Dick Grasso said the decision to reopen is not a question of any one firm’s ability to operate, but it will be a decision based on the entire industry’s operational readiness, the quality of communication, the availability of power, and the safety of buildings down on Wall Street. Grasso emphasized that the exchanges are committed to trading again no later than Monday.

Grasso said the test will be whether the industry is able to serve American investors, and more importantly that it must avoid doing anything that interrupts the recovery operation at the Twin Towers.

Grasso stressed that the decision to proceed with a phased-in return to full operations is a partnership between the primary equity markets, with fixed-income trading starting tomorrow.

The Chicago Mercantile Exchange Inc. has announced that floor and electronic trading of its interest rate, foreign exchange and commodity markets and its Nikkei 225 equity index futures and options contracts will resume at their normal times tomorrow.

Trading of the Nikkei 225 will resume tomorrow in order to accommodate the last trading day of the expiring September contract.

A moment of silence will be observed on CME’s trading floors at 12:00 ET to recognize the victims and survivors of yesterday’s events.