SoftBank’s $66 billion sale of UK-based chip business Arm to Nvidia collapsed on Monday after regulators in the US, UK, and EU raised serious concerns about its effects on competition in the global semiconductor industry, according to three people with direct knowledge of the transaction.

The deal, the largest ever in the chip sector, would have given California-based Nvidia control of a company that makes technology at the heart of most of the world’s mobile devices. A handful of Big Tech companies that rely on Arm’s chip designs, including Qualcomm and Microsoft, had objected to the purchase.

SoftBank will receive a break-up fee of up to $1.25 billion and is seeking to unload Arm through an initial public offering before the end of the year, said one of the people.