UPDATE 2-Mexico's Cemex posts qtrly net profit up 55 pct

(Adds details, analyst quote and byline)

By Noel Randewich

MEXICO CITY, Jan 29 (Reuters) - Mexico's Cemex, the world's No. 3 cement maker, posted net income of $377 million in the fourth quarter on Monday, up 55 percent year-on-year after housing and infrastructure demand boosted sales.

Cemex's (CMXCPO.MX) (CX.N) earnings before interest, taxes depreciation and amortization, or EBITDA -- an indication of cash flow from operations -- rose 4 percent to $934 million.

"The increase in majority net income for the quarter is due primarily to lower depreciation and amortization expense and higher foreign-exchange and financial-instrument gains," the company said.

Cemex had less depreciation and amortization in the quarter than in the year-ago period, when its acquisition of Britain's RMC swelled those costs.

"It was a lower charge than what we saw a year ago, but not as low as we expected," said Carlos Hermosillo, an analyst at Vector brokerage in Mexico City. Revenues rose 13 percent over the year-ago quarter to $4.5 billion, said Cemex, which operates in more than 50 countries around the world.

"Despite the current slowdown in the U.S. residential sector, we experienced strong double-digit sales growth during the quarter both overall and in the majority of our key markets," Cemex's vice president of finance, Hector Medina, said in a statement.

Operating profit rose 21 percent to $611 million, the company said.

Analysts polled by Reuters had, on average, forecast a 123 percent rise in net profit for the quarter and an 8 percent increase in EBITDA.

In the United States, Cemex's top market, net sales fell 11 percent from the year-ago period to $923 million, hurt by a slowdown in the housing market.

HOUSING BOOM

Cemex's operation in Mexico, where the homebuilding industry continues to boom, saw sales of $911 million, up 11 percent. Sales in Spain and the United Kingdom rose 21 percent and 12 percent.

Cemex's net debt at the end of December was $5.8 billion, down $1.33 billion for the quarter and down $2.85 billion for the year.

The Mexican company has made a $12 billion hostile offer to buy Australian firm Rinker RIN.AX RIN.N, although it had received less than 1 percent of the firm's shares as of last week.