Foreign corporate actions are occasionally misunderstood in the US, presenting investors with a fleeting chance to make a quick buck.

When the first tranche of United Utilities' £1bn ($2bn, €1.4bn) rights issue went ex-rights in London on August 27 2003, Joshua Duitz, then a trader at Bear Stearns and now an analyst at Alpine Funds, observed ordinary shares had opened at 465p, off 12.5 per cent from the previous day's close. That is typical of what happens to a share price that goes ex-rights.