Companies potentially affected by last week's European Court of Justice landmark ruling in favour of UK multinationals who have paid stamp duty reserve tax (SDRT) on cross-border share issues should pursue their claims immediately. According to PricewaterhouseCoopers, the strength of the judgment is such that there is no reason to delay. Last week's judgment saw the ECJ rule in favour of the taxpayer in the case of HSBC Holdings plc and Vidacos Nominees Ltd v HMRC. The ruling upheld a decision earlier this year by the advocate general, which found the UK's imposition of a 1.5% tax charge on the issue of shares into a clearance service to be unlawful under EU law. Craig Leslie, head of stamp taxes at PwC, said: 'This is a landmark ruling and the first significant case challenging the UK's SDRT regime for cross-border share issues.' Michael Quinlan, head of stamp taxes at Deloitte, who has been assisting HSBC in the case, said: 'The sum at stake is substantial. Clearly this ruling has implications for many other businesses.' The ruling is likely to lead to claims against HMRC running into billions of pounds.