EasyJet shares rose 12% after the British budget airline said on Monday it would consider any Castlelake takeover proposal, while calling the US investment firm’s ​timing “highly opportunistic”.

Castlelake said on Friday it was in the early stages of considering ​a possible bid for easyJet, but no approach has been made ⁠to its board, and there can be no certainty an offer will be ​made.

It has until June 26 to make a firm bid or walk ​away.

EasyJet responded on Monday by saying it would assess any potential offer if one was made, noting that its stock price is depressed by the Iran war and regulatory and other challenges.

Shares ​in easyJet rose by as much as 12.5% to 447.8 pence in early ​trading, valuing it at £3.39 billion ($4.57 billion). As of Friday, its stock had fallen over 22% ‌so far ⁠this year.

“The Board remains highly confident in easyJet’s strategy and its ability to deliver attractive long-term value for shareholders,” it said in a statement.

While analysts said Castlelake had the financial firepower to bid for easyJet, a full takeover was unlikely ​because of European and ​British regulatory restrictions.

Easyjet warned ⁠last month that its full-year forecast remained uncertain as the Iran conflict drove up fuel costs, while summer bookings were ​behind last year.

Castlelake said separately on Monday it held a ​2.14% stake ⁠in easyJet, making it a top 10 shareholder, LSEG data shows.

The investment firm has aviation sector experience, largely as a lender and aircraft lessor, and has been expanding ⁠its presence ​through a platform backed by billions in capital ​to finance airlines and aircraft assets.