The market darling Toll Holdings and the troubled timber company Gunns had joined the club in recent weeks after shocking the market with their half-year numbers.

Nufarm's ''please explain'' was widely expected, following Tuesday's guidance of a $105 million fall in earnings for the half-year to January. News of the 163 per cent profit slide prompted an immediate 6.3 per cent share price fall when it was delivered at a shareholder meeting called to approve the sale of 20 per cent of the company to Japan's Sumitomo Chemical.

In arguing that it complied with disclosure obligations, Nufarm has provided a compelling response to critics who had speculated that the company's failure to elicit a firm $13-a-share takeover from the Chinese chemical company Sinochem in December might have related to inadequately disclosed poor profitability.

As Nufarm tells it, half-year profitability is invariably difficult to forecast until the period is over, as the seasonality of farming in the US, Australia and Europe results in the vast bulk of sales being recorded in just a few weeks in January. This year, first-half profitability was not fully understood until the afternoon before the shareholder meeting.

In a half that was dragged down by climate and competitive pressures, it was not until the final days of February that Nufarm had a handle on a $33 million trading loss on glyphosate, which the company sells under the Roundup brand.

While Nufarm looks to have complied with its disclosure obligation, with shares trading down to $8.96 following the profit guidance, Sumitomo will be knocked down in the rush as shareholders tender their shares into the proportionate $14-a-share offer.