** Shares of Australian shipbuilder Austal Ltd ASB.AX nosedive 28.5% to A$4.510, their lowest since April 10, 2025

** Stock marks its worst intraday drop since December 2015

** ASB worst performer in the ASX 200 benchmark index .AXJO, which is down 1% as of 2345 GMT

** On Thursday after market close, ASB downgraded FY26 EBIT outlook to A$110 million ($77.98 million) from A$135 million forecast in October

** That also misses the Visible Alpha consensus of A$118.6 million

** Downgrade due to premature recognition of U.S. T-ATS program incentives, resulting in overstatement of $17 million in prior outlook

** About 3 million shares change hands, vs the 30-day average of 1.2 million

** ASB stock down 5.7% this year, excluding the day's move

($1 = 1.4106 Australian dollars)

(Reporting by Sameer Manekar in Bengaluru)

((Sameer.Manekar@thomsonreuters.com;))