MIAMI-Publicly traded shares in MasTec Inc. closed down $3.09 Friday at $14 each, apparently in reaction to a report that First Union Securities downgraded the company’s common stock.

The price per share in the Miami-based provider of communications and energy infrastructure services fell 18.8% on trading volume of 1,645,300.

Although they did not disclose their reasoning, analysts from the sixth largest securities brokerages downgraded the issue Friday to a classification of market-perform from a buy.

Shares in MasTec recently traded as high as $19.01 a share on June 11 but quickly entered into a tailspin that ended Friday with shares closing just $2.60 off the 52-week low of $11.40. The issue has traded as high as $46.92 over the same time period.

News of the stock movement comes as the company last reported a net gain of $3.3 million, or sevem cents a share, on revenue of $337 million for the first quarter ended March 31, compared with a net gain of $11.5 million, or 25 cents per diluted share, on revenue of $272.7 million for the same period in 2000.