James Hardie Industries plunged almost 30% in Sydney trading after the fiber-cement siding maker warned that earnings for the current fiscal year will fall short of analysts’ expectations. The stock slid to A$31.07, the steepest one-day drop in five years, wiping out roughly A$5 billion in market value. The Dublin-headquartered company now projects adjusted operating earnings of US$1.05 billion to US$1.15 billion for fiscal 2026, below the Visible Alpha consensus of about US$1.23 billion and little changed from the US$1.1 billion it posted in fiscal 2025. In the quarter ended 30 June, adjusted net income dropped 29% to US$126.9 million, while revenue in its key North American division—three-quarters of total sales—fell 12% to US$641.8 million. Chief Executive Officer Aaron Erter said elevated U.S. mortgage rates, tariffs and affordability constraints are discouraging both new construction and large-ticket remodeling projects. The company is also absorbing costs tied to the integration of its recent acquisition of decking manufacturer Azek, which some analysts say now looks ill-timed.