NEW YORK (CNN/Money) - DuPont Co. warned that its fourth-quarter earnings would be below its earlier target, saying that only lower tax rates would allow it to be close to current forecasts.

The nation's No. 2 chemical company behind Dow Chemical said it expects to earn between 31 and 33 cents a share in the period, up from 12 cents a share it earned excluding special items a year earlier. Analysts surveyed by earnings tracker First Call expected the company to earn 33 cents a share in the period, with a range of estimates from 30 to 36 cents.

The company said that operating earnings were below company expectations, but that decline should be largely offset by a reduction in the effective income tax rate for the full year. A full earnings report is due Jan. 28.

Shares of DuPont (DD: Research, Estimates), a component of the Dow Jones industrial average, gained 27 cents to $44.00 in trading Tuesday.