Boeing refused to give the Pentagon cost data for almost 11,000 replacement parts over a year, according to a congressionally mandated report intended to shine a light on some military contractors’ opaque pricing data.

The data denials for 10,659 items under a single contract accounted for 97% of such refusals by contractors during negotiations from October 2020 through September 2021, according to a previously undisclosed Pentagon assessment submitted to House and Senate defense committees.