The cost of Boeing's strike keeps rising as talks continue

• Boeing is set to resume negotiations with union bosses on Monday.
• The strike is costing Boeing $50 million a day, a BofA analyst estimated.

Boeing and union bosses are set to return to the negotiating table Monday, over three weeks since workers took to the picket lines.

A group of Bank of America analysts, led by Ron Epstein, estimated that the strike is costing Boeing $50 million a day.

Some 33,000 Boeing workers represented by the International Association of Machinists and Aerospace Workers have been on strike since September 13.

"A resolution with the IAM stands as a priority for me, and our team is ready to resume mediated talks this Monday," Boeing CEO Kelly Ortberg told employees Friday, per Reuters.

When reached by Business Insider, Boeing did not comment beyond confirming that negotiations will resume Monday.

The planemaker has furloughed some staff and barred all workers, including executives, from flying business class to save money during the strike.

Nearly 95% voted against Boeing's initial offer of a 25% pay rise across the four-year contract.

After 10 days on strike, Boeing increased the offer to a 30% wage hike plus doubling the contract-signing bonus to $6,000.

However, IAM District 751's union negotiating committee slammed Boeing's "direct dealing tactics" as "a blatant show of disrespect" — saying this offer was sent to the media while union leaders were still reviewing the details.

They added that they wouldn't be able to table a vote on the renewed offer before the deadline.

Union members have said one key issue is the desire to win back a defined benefit pension lost in 2014 contract negotiations and replaced with 401(k) contributions.

However, District 751 said in an earlier statement that Boeing "remains adamant that it will not unfreeze the defined benefit plan."

Many on the picket line appear willing to continue striking, buoyed by debit cards with a weekly pay of $250 funded by the union.

Boeing is due to report its third-quarter results on October 23. Its stock is down nearly 8% over the past month — and 38% since the start of the year.

Do you work at Boeing? Reach out to this reporter at psyme@businessinsider.com