Boeing Co.’s stock slid 2.8% Wednesday, after the company said it has reached an impasse in its talks with its machinists union to end a strike that estimates say is costing it more than $1 billion a month.

Boeing withdrew a contract offer for 33,000 machinists who have been on strike since mid-September, and said further negotiations “do not make sense at this point.”

Negotiations between airplane maker Boeing and its union broke down this week with both sides pointing the finger at the other for their current standoff with a strike that is approaching one month.