Boeing officially pushed back the timeframe for the 737 MAX's return on Tuesday, saying the jet will not win regulatory approval to resume service before mid-2020.

Boeing has told customers and suppliers "that we are currently estimating that the ungrounding of the 737 MAX will begin during mid-2020," the company said in a statement.

The announcement came while Boeing shares remained halted after tumbling more than five percent following a report of the latest delay in the MAX, which has been grounded since March of last year following two deadly crashes.

Shares resumed trading shortly after the announcement.

The statement is a shift from Boeing's most recent stance on the MAX timeframe, which had withdrawn a target date entirely after repeat timeframes mapped out in 2019 were not met.

Boeing officially pushed back the timeframe for the 737 MAX's return on Tuesday, signaling the jet won't win regulatory approval to resume service before mid-2020
Boeing officially pushed back the timeframe for the 737 MAX's return on Tuesday, signaling the jet won't win regulatory approval to resume service before mid-2020 AFP / Mark RALSTON

But mid-2020 is later than some analysts had expected and also probably represents a best-case scenario for a time-frame that could again be pushed back.

The Federal Aviation Administration had also publicly criticized Boeing for its aggressive timeframe, suggesting the target was a tool for pressuring the agency into approving the plane more quickly.

On Tuesday, an FAA spokesman reiterated that it has set "no timeframe" for the MAX's certification.

"We continue to work with other safety regulators to review Boeing's work as the company conducts the required safety assessments and addresses all issues that arise during testing," the FAA said.

Boeing said its latest time-frame "accounts for the rigorous scrutiny that regulatory authorities are rightly applying at every step of their review."

Shares were down 4.3 percent to $310.18 after trading resumed late in the session.