TOKYO, May 13 (Reuters) - Technology investor SoftBank Group swung to a net profit in the final quarter of its financial year, it said on Monday, as the Japanese giant focuses on artificial intelligence to help fuel a return to growth.

SoftBank booked a profit of 328.9 billion yen ($2.11 billion) in January-March, compared to a loss of 32 billion yen a year earlier. Still, the second straight quarter of profit was not enough to keep it in the black for the full year.

Investors are increasingly focused on the outlook for SoftBank subsidiary Arm Holdings, the British chip designer. Arm's prospects are seen as helping fuel SoftBank's push into AI.

SoftBank has said group assets are AI-focused and that Arm will power companies across the Japanese firm's portfolio.

Still, Arm's surging valuation has not contributed to SoftBank profit as Arm is a subsidiary. Whereas Arm reported record January-March sales on license and royalty revenue, SoftBank booked a 33-billion-yen loss from its Arm investment in the last fiscal year due to increased expenses related to stock compensation and hiring.

Arm's headcount grew by more than 1,100 in the year ended March, with more than 80% of net new hires being in engineering.

Most of SoftBank's investments through its Vision Fund unit suffered valuation loss in the fourth quarter, leaving it with a 57.5 billion yen loss. A bright spot came in the form of South Korean e-commerce firm Coupang which generated around $600 million in unrealised investment gain.

In February, Chief Financial Officer Yoshimitsu Goto said SoftBank - known for volatile earnings and outsized bets on startups - was returning to a "growth trajectory."

Overall, SoftBank's fourth-quarter net profit compared with a 32 billion yen loss in the same period a year earlier, when capital raised using its Alibaba Group stake cushioned writedowns in the value of Vision Fund private portfolio firms.

($1 = 155.8500 yen) (Reporting by Anton Bridge; Editing by David Dolan, Christopher Cushing and Bernadette Baum)