UPDATE 2-Mexico's Cemex 1st-qtr profit rises 18 pct

(Updates with details, analyst reaction; adds byline)

By Robin Emmott

MONTERREY, Mexico, April 21 (Reuters) - Mexico's Cemex, the world's third-largest cement maker, posted an 18 percent rise in first-quarter net profit to $470 million on Monday, slightly above analysts' expectations, despite a U.S. housing slowdown.

Cemex (CX.N)(CMXCPO.MX) said its January-to-March revenues rose 26 percent to $5.4 billion. Earnings before interest, taxes, depreciation and amortization, or EBITDA, increased 10 percent to $951 million, the company said.

Six analysts polled by Reuters forecast, on average, net profit of $438 million, up from $400 million in the year-earlier period.

The earnings were helped by Cemex's sale of its 9.5 percent stake in local telecoms company Axtel (AXTELCPO.MX) in late March for $257 million. Cemex, which operates in more than 50 countries, also posted improved sales in Eastern Europe, Africa and in Central and South America.

"The increase in net income is mostly explained by the gain in financial instruments and other net gains," Cemex said in a statement.

The money from the sales of its stake in Axtel was particularly timely given the U.S. subprime mortgage crisis that has hurt Cemex's residential construction business. Cemex, which last year paid $16 billion for Australian rival Rinker, also faces an economic slowdown in its two other major markets, Mexico and Spain.

Francisco Chavez, a cement analyst at BBVA Bancomer, said the gain in net profit was strong because of the inclusion of the Rinker operations this quarter.

Cemex acquired Rinker in June last year and began including those operations in the third quarter of 2007.

"On a like-to-like basis, stripping out Rinker, Cemex's total sales fell 3 percent in the quarter," Chavez said.

Even with Rinker, which gave Cemex a big boost in its U.S. operations, the company's EBITDA in the United States decreased 8 percent to $164 million in the first quarter, compared with the year-ago period.

Cemex's U.S. volumes fell 3 percent in the quarter.

For Cemex, which competes globally with Switzerland's Holcim (HOLN.VX) and France's Lafarge (LAFP.PA), the fall in U.S. housing construction has been particularly severe in its high-growth markets such as Florida.

Meanwhile, higher energy costs took their toll on Monterrey-based Cemex's overall operating income, which fell 17 percent to $461 million in the first quarter.

"The aggregate cost of energy and electricity per ton of cement produced for our portfolio increased by approximately 16 percent during the quarter compared with the same period last year," the company said. (Additional reporting by Gabriela Lopez, editing by Carol Bishopric)