Metromedia Inc., the communications industry conglomerate that offers the highest priced stock on the New York Stock Exchange, today announced a 10-for-one common stock split.

The company, which owns WTTG-TV in Washington as well as six other major market television stations, made the move to increase the liquidity of the stock and broaden investor representation, according to Metromedia Chairman John W. Kluge. The stock closed trading today at $550 a share, unchanged.

"I am happy to see that the company has gone public again," joked Fred Anschel, an analyst with Dean Witter Reynolds Inc. "When a stock trades for those kinds of prices, it's not really public in the true sense of the word."

The 10-for-one split--one of the few of that magnitude analysts could recall--had been expected for some time. Under the terms announced by the company, shareholders as of July 15 will receive nine additional shares for each one they own. The number of outstanding shares will rise to 29.4 million, 10 times the pre-split figure.

In the last two months, the stock has gained 160 points, up from a 52-week low of 191 1/4 and a record low of 4 1/4 nine years ago. Just yesterday, it gained a staggering 37 points.

Analysts generally have been high on Metromedia because of its broadcast properties in major markets. In recent years, the company has added stations in Chicago and Boston to its string in major markets. Of late, however, Wall Street enthusiasm has risen as a company diversification and expansion strategy has made it a leading potential player in cellular mobile radio.

Metromedia has filed 16 applications with the Federal Communications Commission to offer the mobile telephone service and also has bought five radio paging companies.