Smartphone chip designer ARM Holdings is to announce that it is being bought by Japan's SoftBank for more than £23bn, according to reports.
The board of the Cambridge-based firm, which supplies technology for Apple's iPhone, is expected to recommend shareholders accept the offer, the BBC reported.
In April, the company cheered rising profits as it outpaced the market thanks to a strong demand for its products.
The BBC said it understands that telecommunications and internet firm SoftBank will commit to doubling the size of ARM's UK workforce over the next five years.
The Wall Street Journal said the deal was expected to be announced this morning.