For the second time within a week, a major Downtown office building has been sold to an out-of-town investor.

The National City Center, a 22-story tower at Stanwix and First streets, was sold yesterday to National City Center Limited Partnership, a New York-based private investment group, for $23 million.

While the sale price matches the county's assessment of the building for tax purposes, the fact that it works out to $67 per square foot puts the deal in bargain territory. In 2004, the region's office space sold for an average $71 per square foot, but the national average was more than double that, at $165 per square foot.

National City Bank is the building's primary tenant, occupying 50 percent of its 343,000 square feet. The building's total occupancy is 70 percent.

Designed by the renowned architectural firm of Skidmore, Owings and Merrill, the building began its life in 1982 as the corporate headquarters for the now defunct National Steel, and also has been home to the Federal Home Loan Bank and law firm Thorpe Reed Armstrong.

The sale follows last Wednesday's sale of the nearby Verizon building, at 201 Stanwix St., to California-based Hertz Investment Group for approximately $6 million.

The two sales represent a trend, said Jeffrey B. Ackerman, executive vice president at CB Richard Ellis, who helped broker the National City transaction. Mr. Ackerman said 70 percent of his sales during the past two years had been to out-of-state buyers.

"It's unusual today to get [the listing on] a property and wind up selling it to a local buyer," he said.