Vitech America

(VTCH)

and

Gateway

(GTW)

have filed breach of contract lawsuits against each other, stemming from a 1999 agreement covering the distribution of computer products in Brazil.

Shares of both companies lost ground in today's trading session. Vitech plummeted 55% in recent

Nasdaq

activity, falling to $1.38, while Gateway, which is based in San Diego, shed 7% to $14.95 on the

New York Stock Exchange

.

Vitech, which sells computer-related products in Brazil, alleges that Gateway misrepresented a series of agreements beginning in 1999. Vitech, which is based in Miami, filed the suit in a U.S. District Court in Florida.

"The allegations are baseless and we will contest them vigorously in court if necessary," Gateway said.

Gateway is countersuing Vitech in New York.