TOKYO (Reuters) -Japanese technology investor SoftBank Group booked a net loss of 369.2 billion yen ($2.4 billion) in the October-December quarter as valuations at its Vision Fund investment arm fell.

The loss will further raise questions about SoftBank's plans for one of its most ambitious undertakings - a hefty investment in OpenAI.

Sources said in January that SoftBank was in talks to invest up to $25 billion in the ChatGPT creator. Recent media reports have said that figure has grown to $40 billion though some of that amount would later be syndicated out to other investors.

SoftBank has also committed to investing $15 billion in Stargate - a venture with OpenAI and Oracle that will build AI data centre capacity in the United States and which has has been backed by U.S. President Donald Trump.

The third-quarter result compares to an LSEG consensus estimate of a net profit 234 billion yen drawn from four analysts and a profit of 950 billion yen in the same period a year earlier.

The Vision Fund unit posted an investment loss of 352.7 billion yen, breaking a run of two consecutive quarters in the black.

Vision Fund 1 has had a gross gain of $21.6 billion since its inception in 2017 while Vision Fund 2, which covers a broad suite of earlier-stage startups, has logged a $22.2 billion loss since 2019.

($1 = 153.6000 yen)