DuPont

(DD) - Get Report

reported a higher-than-expected 20% increase in first quarter earnings Tuesday but the leading American chemical company's share price tumbled on expectations that earnings would weaken later in the year.

Income from continuing operations rose to $898 million, or 85 cents a diluted share, compared with $749 million, or 69 cents a share in the year-ago period. Including one-time items, earnings per share were $803 million, or 76 cents, compared with $663 million, or 58 cents, in first quarter 1999. Revenues for the quarter rose 21% to $7.59 billion.

Wall Street had expected DuPont of Wilmington, Del., to post earnings of 74 cents a share, according to a survey conducted by

First Call/Thomson Financial

.

DuPont's share, however, closed down 4 7/8, or 8.7%, at 51 1/8.

Paul Leming, an analyst with

ING Barings

, attributed the drop in the share price to the company's indications that future earnings would not be as strong as previously estimated.

"I did walk away from the conference call with a sense that earnings were less rosy than the picture the company had painted a month ago," said Leming, who rates the company a hold and has not done any underwriting for it.

During the call, DuPont officials warned that it would not begin reporting profits from Cozaar, a blood pressure treatment drug it jointly produced with

Merck

(MRK) - Get Report

, until 2001 rather than third-quarter 2000. This will cut DuPont's earnings by about a nickel for both the third and fourth quarter.

Analysts were also shaken by Dupont's announcement that profits from its pension accounting would be higher than expected by anywhere from 5 to 11 cents for the year. Although expectations of higher profits usually help to drive up stocks, Leming said he was not impressed by a bigger bounty from pension accounting.

"An analyst would like to feel that you are investing in DuPont because they are operating their plants well," said Leming.

In addition, DuPont shifted the reporting cycle for its recently acquired

Pioneer Hi-Bred

seed company so that the first quarter would run from January through March, rather than December through February. This means that sales in March, typically the strongest month, will no longer be a factor in second-quarter earnings.

"Now we'll have to hone the numbers for the second quarter," Leming said.

A First Call/Thomson Financial survey indicated that analysts had previously expected DuPont to post earnings of 98 cents and $3.03 for the second quarter and the year, respectively.