--Merval index closes lower, in part on concern the government might act against some companies

--Bonds end mixed, with GDP warrants down

--Black-market peso steady

 
   By Taos Turner

BUENOS AIRES--Argentine stocks fell Friday, as concern mounted among investors that the government may take some kind of action against one or more of the stock index's top firms.

The Merval fell 1% to 2381.96, and volume totaled ARS40 million ($8.6 million). The index is down 1.1% on the week.

"Argentina does not have a good investment climate," said a trader.

Steel-sheet producer Siderar SAIC (ERAR.BA) led the declines, sliding 5.2% to ARS1.27.

Siderar's shares fell after Argentine President Cristina Kirchner and Deputy Economy Minister Axel Kicillof this week publicly slammed Paolo Rocca, the head of Siderar's parent conglomerate, Ternium SA (TX). Mr. Kicillof called Mr. Rocca ignorant and said he had acted in bad faith after a local newspaper reported Mr. Rocca had questioned the wisdom of government policies.

Mr. Rocca reportedly said the government lost its way in 2008 and has been pursuing policies that have made the country less competitive ever since. His comments infuriated Mrs. Kirchner and Mr. Kicillof, who said Mr. Rocca should be grateful for government policies, including energy subsidies offered to the company.

Meanwhile, shares of the phone company Telecom Argentina (TECO2.BA, TEO) fell 4.2% after Planning Minister Julio De Vido earlier this week canceled plans to auction off wireless 3G spectrum to mobile phone companies, including Telecom.

Additionally, Mr. De Vido said he would revisit the complex shareholder structure that links Spain's Telefonica SA (TEF.MC, TEF) to Telecom Argentina. Telefonica holds an indirect stake in Telecom as a result of a convoluted transaction in which the Spanish firm obtained an interest in Telecom Italia SpA (TI, TIA, TIT.MI) in 2007.

Argentina's government at one time opposed that deal on the grounds the Telefonica and Telecom Argentina tie-up had created a virtual monopoly. But Argentina's antitrust agency approved the arrangement in 2010 when Telefonica agreed to give Argentine minority investors sweeping powers in Telecom Argentina.

Mr. De Vido's comments fueled speculation the government may be preparing for some kind of move against Telecom or, at a minimum, greater intervention in the telecom sector.

A spokesman for De Vido couldn't be reached for comment.

State-run oil-and-gas company YPF SA (YPFD.BA, YPF) led gains, rising 0.8% to ARS83.50.

Bonds were mixed.

The TVPP GDP warrant fell 0.14% to ARS14.38.

The peso closed at ARS4.660 to the U.S. dollar on the MAE foreign-exchange wholesale market, compared with ARS4.6550 in the previous session.

The dollar traded for about ARS6.35 in the black market, little changed from the previous session, according to the newspaper El Cronista.

Write to Taos Turner at taos.turner@dowjones.com