ASX ends lower; BHP, Rio weigh on market Save Share Austal bears biggest hit from US tax hike among ASX companies Vesna Poljak Joe Bidenâs plan to raise Americaâs corporate tax rate would have the biggest earnings impact on Austal, Appen, and James Hardie, according to Macquarie analysis, which concludes they might still be better off as probable beneficiaries of Bidenâs infrastructure spending. The intended tax increases are required to fund the administrationâs $US2 trillion ($2.6 trillion) plan to rebuild Americaâs transport infrastructure, utilities and other policy needs, by increasing the company tax rate to 28 per cent from 21 per cent.