Network Solutions Inc., the Herndon firm that assigns most of the world's Internet addresses, said yesterday that strong demand for its address-registration services pumped up second-quarter profit, which increased 135 percent, to $5.8 million (17 cents a share) from $2.5 million (7 cents). Revenue in the quarter surged 132 percent, to $47.5 million, from $20.5 million a year ago.

The company said its profit was driven by registering a record 1.2 million new addresses, or "domain names," in the quarter. Network Solutions registers addresses with the popular ".com," ".org" and ".net" suffixes.

Network Solutions, which at one time had an exclusive arrangement with the U.S. government to register addresses that end in ".com," faces competition from several other firms that also have been given the right to register addresses with the same suffix.

Network Solutions currently is negotiating terms of competition with the Clinton administration and a new nonprofit corporation set up to manage the process.

For the first six months of its fiscal year, Network Solutions' net income increased 135 percent, to $10.6 million (30 cents) from $4.5 million (14 cents). Revenue in the period rose 132 percent, to $85.6 million from $37.0 million.

Network Solutions stock closed at $71.87 1/2, down $5.37 1/2, in trading yesterday on the Nasdaq Stock Market.

Advanced Communication Systems Inc. of Fairfax, which provides communication, aviation and information technology services and solutions to government agencies and commercial customers, said acquisitions and internal growth lifted revenue and profit in its third quarter.

ACS said net income grew to $2 million (23 cents), from $1.2 million (16 cents) in the year-ago quarter. Revenue increased 123 percent, to $57.6 million from $25.8 million.

ACS shares yesterday closed at $13.93 3/4, down 37 1/2 cents, in trading on the Nasdaq Stock Market.

AES Corp. of Arlington, a global power company, reported higher earnings in the second quarter before deducting a $146 million loss in a foreign currency transaction.

AES said its net income was flat at $71 million (36 cents), compared with $71 million (39 cents) in the year-ago quarter. Second-quarter revenue rose 13 percent, to $640 million from $565 million.

The company's revenue was driven by acquisitions of power plants and electric distribution companies worldwide. In June, AES said it assumed management control of two regional electric distribution companies in Kazakhstan, as well as permission from Kazakhstan to export power to Russia.

For the first half of the year, AES said net income was $58 million (31 cents), compared with $136 million (75 cents) for the same period last year, excluding foreign currency losses.

AES shares closed yesterday at $54.31 1/4, down $1.37 1/2, in trading on the New York Stock Exchange.

Choice Hotels International of Silver Spring, the nation's second-largest hotel franchisor, said its second-quarter profit rose 12 percent, to $14.5 million (26 cents), from $13 million (22 cents) for the same period a year ago.

For the first six months of 1999, Choice reported profit of $24.8 million (44 cents), an increase of 17 percent from the $21.1 million (35 cents). The company attributed the strong increase in revenue from higher growth in online reservations, and higher royalties.

Second-quarter revenue rose to $38.4 million, a 3 percent increase from $37.2 million for the same period a year ago.

For the first six months, revenue increased 5 percent, to $67.2 million from $64.1 million.

Choice closed at $15.93 3/4, down 6 1/4 cents, in trading on the New York Stock Exchange.

Lafarge Corp., a Reston construction materials company, said second-quarter net income rose to $88.6 million ($1.22), from $85 million ($1.17) a year ago.

Second-quarter sales increased 7 percent, to $720.2 million from $674.8 million.

Lafarge's stock closed at $32.06 1/4, up 6 1/4 cents trading on the New York Stock Exchange.

NVR Inc. of McLean, parent of Ryan Homes and NV Homes, earned $28.3 million ($2.26) in the second quarter, compared with $8.8 million (65 cents) in the same quarter last year when results were pulled down by a $6.7 million extraordinary loss due to early debt payoff. Without that one-time loss, profit rose 82 percent. Revenue rose 27 percent, to $508.9 million from $399.9 million.

NVR also runs a mortgage lending company, and that operation is beginning to be pinched because rising interest rates mean many fewer people are refinancing loans. To deal with that, NVR this month began to consolidate its mortgage banking.

For the first six months, NVR earned $54.3 million ($4.28), compared with $19.6 million ($1.46) in the same period a year earlier. Revenue rose 36 percent, to $955.5 million from $701.3 million.

NVR's stock yesterday fell 56 1/4 cents, to $56.50, in trading on the American Stock Exchange.

Potomac Electric Power Co. reported net income of $75.3 million (61 cents) for the second quarter, up 14 percent from $66 million (46 cents) for the same period in 1998.

The company said that its revenue during the second quarter of 1999 was $544.6 million, up from $528.5 million in the same period a year earlier.

For the first six months, the company reported net income of $101.3 million (81 cents), up from $73.5 million (50 cents) during the first six months of 1998.

Revenue in the first six months of 1999 was $973.6 million, up from $908.9 million a year before.

The earnings in the first six months of 1999 included the net effect of a contract termination fee to be received from the Southern Maryland Electric Cooperative Inc. in January 2001.

The contract termination fee compensates Pepco for future earnings that would have been received under the 10-year power supply requirements contract.

The contract required Pepco to provide electric power to Smeco but was canceled in January of this year. Pepco booked a portion of the payment to be made in January 2001 to earnings in the first quarter of 1999.

Pepco's stock price closed at $30.75, up 31 1/4 cents, in trading yesterday on the New York Stock Exchange.

Ryland Group Inc. of Columbia said profit in the second quarter doubled to $17.6 million ($1.12) from $8.8 million (57 cents) a year earlier. Revenue rose 18 percent, to $502.4 million from $425.9 million.

Ryland said that profit increased much more steeply than revenue because a strong market enabled it to operate more efficiently and make more profit on each house.

In the first six months of the year, profit rose 105 percent, to $27.7 million ($1.76) from $13.5 million (86 cents).

Revenue for the first six months rose 19 percent, to $906.4 million from $762.2 million.

Ryland's stock price closed at $28, down 87 1/2 cents, in trading yesterday on the New York Stock Exchange.

United Payors & United Providers Inc. of Rockville, which runs a network of health care providers, said it earned $6.5 million (34 cents) in the second quarter, up 35 percent from $4.8 million (27 cents) during the same period a year ago.

Revenue for the quarter rose 42 percent, to $27.2 million from $19.1 million.

For the six months that ended June 20, earnings rose 31 percent, to $12.1 million (65 cents) from $9.2 million (51 cents).

Revenue for the six-month period rose 35 percent, to $50.9 million from $37.7 million.

United's stock price closed at $22.25, up 50 cents, in trading yesterday on the Nasdaq Stock Market.

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