Marathon Oil Corp.warned of a“mass layoff”involving more than 500 employees at its Houston headquarters as part of the$17 billion takeover by ConocoPhillips,according to state filings.

The affected workers“may reasonably expect to experience a permanent loss of employment during the 12-month period”following closure of the transaction,Marathon said in a notice to the the Texas Workforce Commission released on Wednesday.

The date of the layoffs was listed in a state database as May 28,the day before the merger was publicly announced,although the full filing indicates the reductions are in may cases months away.

“There will be a mass layoff at the Houston Facility wherein at least 500 employees will experience an employment loss,”the filing said.

ConocoPhillips expects to make$500 million in cost and capital savings in the first year of the takeover,which is expected to close during the current quarter.

Marathon didn’t respond to a request for comment.A ConocoPhillips spokesperson referred inquiries to Marathon.

（Picture: Veer）