Its shares are outperforming those of many of its rivals, rising 8.3 percent this year, to close on Friday at 42.40 euros.

Such problems have been rare in that industry, and this one could presage the end of an era that saw shares in food companies outperform nearly all other industries.

Over the last three years, shares of fund companies like Franklin Resources and T. Rowe Price outperformed the best mutual funds that they managed.

With the exception of the Pacific Telesis Group, the shares of the Bells have outperformed the Standard & Poor's 500 index since July.

Moreover, shares of telephone companies have outperformed most stock indices this year.

Apple's shares have outperformed Microsoft's.

They found that where the market value was 85 per cent or less of that predicted by the model, shares outperformed the market.

While the S.E.C. argued that A shares always outperform B shares, the administrative judge found that not to be the case.

Since then, the shares have risen by 50pc and paid the largest dividend in the sector, outperforming the FTSE All Share by 55pc.

The company's shares, after being listed in the United States late in 1986, outperformed the market.