Arm, the British chip-designer owned by SoftBank Group, is likely to aim to raise at least $8 billion from what is expected to be a blockbuster U.S. stock market launch this year, people familiar with the matter have said.

Arm is expected to confidentially submit paperwork for its initial public offering in late April, the two sources said, speaking on condition of anonymity because the discussions are confidential. The listing is expected to happen later this year and the exact timing will be determined by market conditions, the sources added.

SoftBank has picked four investment banks to lead what is expected to be the most high-profile stock market flotation in recent years. Goldman Sachs Group, JPMorgan Chase, Barclays and Mizuho Financial Group are expected to be the lead underwriters for the deal, the sources said, adding that no bank has been picked for the much-coveted "lead left" position yet.