By Carla Mozee

Mexican and Brazilian equities finished lower Wednesday, tracking a pullback on Wall Street, where ongoing weakness in the U.S. housing sector and a downgrade of Portugal's credit rating rekindled global growth worries.

Mexico's blue-chip index posted its first loss in eight sessions, with shares of Cemex (CX) tumbling 4.1% after the cement maker warned of a first-quarter loss. The IPC index fell 0.6% to 33,160.97.

Brazil's Bovespa fell 0.7% to 68,913.40, with just a handful of stocks finishing higher. But shares of market heavyweight and state-run oil giant Petrobras (PBR) pulled out a win, rising 0.8%, and credit processor Redecard rose 2.8%.

On Wall Street, the Dow Jones Industrial Average (DJI) and the S&P 500 Index (SPX) each fell 0.5%, giving up earlier gains following a downgrade of Portugal's long-term credit rating by Fitch Ratings to AA- from AA.

European equity markets also fell following the downgrade decision by Fitch, which cited "significant budgetary underperformance in 2009," as a key reason for the move. Earlier this month, Moody's Investors Service warned that debt and deposit ratings of Portuguese banks are at risk from a potential downgrade.

The downgrade of Portugal arrived amid lingering uncertainty over aid efforts for debt-strapped Greece by the European Union.

Meanwhile, the U.S. Commerce Department said demand for U.S.-made durable goods rose for a third consecutive month, up a seasonally adjusted 0.5% to $178.1 billion in February.

But monthly housing figures from the department were much less upbeat, as sales of new homes fell for the fourth straight month. Sales dropped 2.2% to a seasonally adjusted annual rate of 308,000 in February, the lowest rate since the government began recording the data in 1963.

"The recent bout of worry on the housing market does not appear to be going away," Jennifer Lee, senior economist at BMO Capital Markets, wrote in a note to clients.

Lee also highlighted that the government's homebuyer tax credit "does end in a little over a month...then that's it for government incentives." Contracts must be entered by April 30, and closed before July 1, she wrote.

In trading action, Cemex shares led decliners in Mexico City. In a filing with the U.S. Securities and Exchange Commission, the company said it will likely report a consolidated net loss for the first quarter.

The "global economic crisis has continued to negatively affect the demand for our products in many of the markets in which we operate," said Cemex in the filing. "In addition, severe winter weather conditions in the U.S. and Europe have negatively affected our operations in such markets during the period."

Meanwhile, shares of America Movil (AMX) slipped 0.2%. The region's largest wireless services provider on Tuesday raised $4 billion through the sale of debt.

But Empresas ICA (ICA) was among the few advancers in the Mexican equity market, rising 0.8% after the engineering and construction giant won contracts for two low-sulfur gas projects from Mexican state-run oil firm Pemex. The contracts are valued at $622 million. The projects are part of Pemex's clean fuels program, the company said.

ICA Fluor, the company's joint venture with Fluor Corp. (FLR), will book its $311 million portion of the award in the first quarter of this year.