** Shares of Australia's ARB Corp ARB.AX plunge 20% in early trading to A$19.690, their lowest since early August 2020

** ARB biggest loser on the ASX200 benchmark index .AXJO, marking its worst intraday performance since late March 2020

** About 410,000 shares change hands, vs. 30-day average of 402,600 shares

** ARB, which makes and sells four-wheel-drive parts and accessories, posts 1H26 attributable profit of A$42.2 million, 17.2% lower than last year and below Visible Alpha consensus by about 1%

** HY revenue also down 1.2% to A$362.2 million, missing consensus of A$363.2 million

** Co says Australian aftermarket remains challenging, with new vehicle supply of key four-wheel-drive models continuing to trail last year

** Says 2H26 performance expected to be better than 1H26, trading closer to the corresponding period of the previous year

** As of last close, ARB down 21.9% this year, compared with a 3.6% gain in the ASX200 index

(Reporting by Sameer Manekar in Bengaluru)

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