Chemical maker

Union Carbide


released a partial report on first-quarter earnings Wednesday, which beat Wall Street expectations despite weaker results from its core chemicals and polymers units.

The Danbury, Conn.-based company, which

Dow Chemical

(DOW) - Get Report

is in the process of acquiring, said its first-quarter earnings rose to 71 cents a diluted share, compared with 56 cents a share for the same period last year. The results exclude changes in accounting methods.

Union Carbide did not release a more detailed accounting of earnings and did not provide revenue data. It was not immediately clear why, but the company said it would issue a full report May 1.

The company's shares fell 1 7/3 or 3.3% to 54 5/16 by midday on the

New York Stock Exchange

. (Union Carbide closed down 2 1/16, or 4%, at 54 1/8.)

Union Carbide's per-share results beat

First Call/Thomson Financial

estimates for 69 cents a share. Estimates had been raised on March 30, when Union Carbide said earnings would be higher than First Call's estimate at that time for earnings of 54 cents a share.

In a statement, Carbide's chairman and chief executive William H. Joyce said the company's profitability was hurt by lower basic chemicals and polymers earnings, though the weakness was offset by changes in its pension plan and a reduction in its environmental-related costs.

He noted the company was able to raise prices for many of its chemicals, but overall increases did not offset the cost of raw materials such as crude oil, natural gas and ethylene.

The earnings report might be the last for the 87-year-old company, which Dow Chemical is planning to acquire by the end of the second quarter. Dow agreed to buy Carbide last August.