DESCRIPTION: Washington-based electric utility serving a 643-square-mile area that includes D.C., a small portion of Arlington County in Virginia (including the largest customer, the Pentagon), the populous Maryland suburbs and, through sales to a cooperative, Southern Maryland. (NYSE, Phila., M). 1979 PROFITS PER SHARE: $1.73. DIVIDENDS: $55.8 million ($1.355 a share, since increased to $1.40 a year). FOUNDED: 1895.

TOP EXECUTIVE: W. Reid Thompson, chairman and president.

Although electricity rates rose last year and applications for higher rates now are pending before regulatory agencies, Pepco's officers expect that rate increases in future years won't match inflationary trends generally because the utility does not have to spend heavily for new construction to expand service capacity. Pepco also does not rely on oil; last year, 76 percent of its energy needs were met by coal. Pepco received a 3.8 percent rate boost in Maryland last year and, in D.C., a rate hike of 2 percent. Both increases in basic base rates were the first since late 1976. The average price per kilowatt hour, including fuel,for all customers rose 2.9 percent in 1979 over the previous year, while overall consumer prices jumped 13 percent. Pepco now is seeking rate hikes of 12 percent ($48.5 million) in Maryland and 15.4 percent ($48.1 million) in D.C., plus 10 percent ($1.6 million) in Arlington County. Pepco says it has based its rate requests on the difference between actual profits and rates of return already permitted. About 97 percent, or 115,000, of Pepco's stockholders are individuals; the average holding is 213 shares.