(Bloomberg) -- The US Justice Department must decide by August 5 whether it will seek to block a tie-up between Alaska Air Group Inc. and Hawaiian Holdings Inc., the airlines said in securities filings on Tuesday.

The airlines said they had turned over all documents requested by antitrust enforcers, triggering a 90-day deadline for a decision that will expire on August 5.

The agency opened an in-depth review of the transaction in February. The Biden administration has taken a tough stance on airline mergers suing to break up a partnership between American Airlines Group Inc. and JetBlue Airways Corp., and to block JetBlue’s proposed deal to buy Spirit Airlines Inc.

Read More: Alaska-Hawaiian Deal Doubts Mount After JetBlue-Spirit Blocked

Alaska’s proposal values Hawaiian’s equity at about $1 billion, and includes about $900 million of debt. Alaska will be the parent holding company, headquartered in Seattle, with Alaska Airlines and Hawaiian Airlines continuing to operate under their separate brands.

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