** AI infrastructure firm Nebius Group's NBIS.O shares fall 4.6% to $84.49
** Co's capex increases to $2.13 billion in Q4 2025, compared with $416 million in Q4 2024
** Despite posting an over sixfold increase in Q4 revenue to $227.7 million, NBIS misses analysts' estimates of $246.1 million - data compiled by LSEG
** Co expects to have more than 3 GW of contracted power by year-end, up from prior outlook of over 2.5 GW
** As of last close, NBIS has more than doubled in the last 12 months
(Reporting by Anhata Rooprai in Bengaluru)
((Anhata.Rooprai@thomsonreuters.com))