** Shares of Austal ASB.AX fall as much as 13.5% to A$5.45, hitting their lowest since February 16

** Stock down after five straight sessions of gains, marks weakest intraday trading session since February 13

** Shipbuilder says co's H2 FY2026 will not match elevated earnings recorded in H2 FY2025, which included significant profit contribution from facilities expansion contract in the U.S.

** Broadly, market sentiment weak after U.S. President Donald Trump raised temporary global tariff rate to 15% on the rest of the world over the weekend

** YTD, stock down 15.1%, including the day's moves

(Reporting by Shivangi Lahiri in Bengaluru)

((shivangi.lahiri@thomsonreuters.com))