Cement Firms Dumping, U.S. Rules : Trade: The finding that Mexican producers are selling at below-market prices has caused an uproar south of the border.

A ruling that Mexican cement makers have gained a major share of the U.S. market by selling at below-market prices has caused a furor in Mexico, where it is viewed as protectionist and likely to stifle export-oriented investment.

That perception of the U.S. Commerce Department’s preliminary ruling Friday was accentuated because Cementos Mexicanos, a company lauded as an example of Mexican economic modernization, will be hardest hit. The company’s sales to the United States are likely to be subject to a 56.7% tariff.

U.S. cement makers see the issue as simply a question of fair pricing, but for business interests here it casts doubt on whether Mexican exports will be accepted in the United States, according to Juan B. Morales Doria, president of Mexico’s Business Round Table.

He added that the Mexican business community has been following the cement dumping case closely.

Cementos Mexicanos’ problems could well discourage other potential exporters and dampen their enthusiasm for making the investments they need to enter the international market, said Juan Jose Mercado, spokesman for the Mexican Assn. of Importers & Exporters. To counteract that negative effect, he said: “We have to make sure that companies know the rules of international exporting and realize they have to abide by those rules.”

Specifically, the Commerce Department found that Mexican cement makers’ prices are lower in the United States than in Mexico, the first step in proving a dumping case. The second step is a hearing, scheduled for June, to determine whether U.S. manufacturers were harmed by the underpricing.

Between now and then, U.S. companies that import Mexican cement must post a bond to cover the tariff expected to be levied.

“The bond makes its uneconomic to bring in Mexican cement,” said Karen Twitchell, spokeswoman for Houston-based Southdown Inc., one of seven U.S. companies that filed the complaint.

The ruling affects all Mexican cement exporters. However, because Cementos Mexicanos supplies 85% of the cement Mexico sells to the United States and depends on exports for one-third of its sales, it is the company most affected by the ruling.

Company officials would not comment.

Last year, Cementos Mexicanos took on $1 billion in debt and sold off peripheral assets to finance aggressive acquisitions that allowed it to become a major cement supplier in Texas, Florida, Arizona and New Mexico. The company’s $34-million deal to buy an import terminal at the Port of Los Angeles that could supply one-fourth of the Southern California market is said to be in jeopardy because of the dumping ruling.

“It’s going to hit them hard,” said Alavaro Altuzarra, who follows the company for Acciones y Valores, a Mexican brokerage firm. The company already is so highly leveraged that it is in violation of its debt agreements, according to its annual report.

Cementos Mexicanos had expected to improve its balance sheet by selling stock in one of its four cement-producing subsidiaries. Analysts were not sure whether the ruling would affect that offering or the $602-million, four-year expansion the company announced in mid-1989.