CME Group said technical issues had shut down contracts on its Globex electronic trading system on Tuesday afternoon with primarily agricultural and grains contracts affected and no impact on oil or metals.
Trading continued in the open outcry pits on the floor of the Chicago Board of Trade. Shutdowns on the electronic trading system are rare.
"We can confirm that we are experiencing technical issues ... we are working to get this resolved," CME spokesman Chris Grams said.
CME said all grain futures and options currently halted on CME Globex will be settled Tuesday via open outcry methodology.
CME posted this message on its website earlier: