Austal shares rose 6% after news broke of a bid valuing its U.S. business at up to $1.35 billion, according to wire reports. The Australian shipbuilder, which builds vessels for the U.S. Navy, has drawn interest in its American unit specifically rather than the whole group.

The size of the offer is notable relative to Austal's overall market value, and the stock move suggests investors see the deal as a clear win for shareholders if it closes. Details on the buyer and deal structure were not fully specified in available reporting.

What remains open is whether the bid converts into a signed, binding transaction, and at what final price. Regulatory review of any sale touching U.S. Navy shipbuilding assets would likely take time given the defense-sensitive nature of the business.