UPDATE 2-Mexico's Alfa reports more than 90 pct fall in 3rd-qtr profit

(Corrects sixth paragraph to show Leal spoke on a conference call with reporters not analysts)

MEXICO CITY, Oct 17 (Reuters) - Mexican conglomerate Alfa on Monday reported a more than 90 percent fall in third-quarter net profit, compared to the same period last year, hurt by higher administrative and financial costs.

Monterrey-based Alfa, which makes car parts and sells processed foods, reported a profit of 234.5 million pesos ($12.1 million).

Revenue rose 11.8 percent to 75.3 billion pesos, as the weak peso raised the value of its income in U.S. dollars.

The peso has been hit by fears that Donald Trump could clinch the U.S. presidency. Trump has vowed he would build a wall on the border with Mexico and renegotiate or scrap the North American Free Trade Agreement if he is elected.

Ramon Leal Chapa, Alfa's chief financial officer, said the company continued to suffer from low economic growth and volatility in oil prices.

"The good news is that by the end of the quarter, there was more stability than in the beginning," Leal said on a conference call with reporters.

The company's administrative costs rose by more than one third from the year-earlier quarter to 5.2 billion pesos.

Sigma, its frozen foods division, saw consolidated earnings before interest, tax, depreciation and amortization (EBITDA) fall some 20 percent from the year-earlier quarter, according to a company press release.

Leal said the decline was misleading because the division had collected insurance coverage in the third quarter of 2015 due to damages and losses associated with a fire at its CFG plant in Burgos, Spain.

"Excluding these two factors, i.e. the insurance collection and the effects of the exchange rate, the (cash) flow would have increased 8 percent, which is positive in an environment of low economic growth," he said.

The company said there was no date for a possible initial public offering of the Sigma subsidiary, a plan that the Mexican conglomerate had floated in 2014 to lower its debt burden.

Alfa revised lower its 2016 sales outlook in July, after it posted a sharp drop in profits in the second quarter.

($1 = 19.3820 at end-September) (Reporting by Mexico City Newsroom; Editing by Bernard Orr)