One of St. Paul's most recognizable towers is being purchased by one of the city's biggest property owners.

St. Paul-based Madison Equities said Monday it signed an agreement with Nightingale Realty of New York to buy the First National Bank Building, a landmark for more than 80 years known by the glowing red "1st" sign at its peak.

"The building is in remarkably good condition, provides many amenities for tenants and is well occupied," said Jim Crockarell, president of Madison Equities. "It fits in with our portfolio, we can manage it efficiently, it's a logical expansion of our existing portfolio. We like St. Paul and have been an active part of the market for over 40 years."

The sale is expected to close next week. Terms weren't immediately disclosed.

Madison Equities focuses on downtown St. Paul buildings and suburban strip malls. The firm owns about 15 buildings in downtown St. Paul, including some of the city's highest-profile office buildings, such as U.S. Bank Center. It also owns four restaurants within its properties. Crockarell said the company is working on four more restaurants, also within its buildings, for the coming year.

About 660,000 square feet of the building at 332 Minnesota St. is rentable to office users. The building is about 1 million square feet when including the common areas, fitness facilities and conference center. It includes a 400-stall parking garage.

"I would pat the existing owner on the back," Crockarell said, adding that fine work has been done "over the course of the ownership."

Nightingale purchased the complex in June 2012 for $19.8 million.

Crockarell said the North and West buildings are about 85 percent occupied and he anticipates that to be closer to 90 percent at the time of closing. Meanwhile, he has plans for the East building.

"The East building is scheduled for redevelopment, but we haven't made any firm decisions yet," Crockarell said.

For 55 years, the First National Bank Building — or the West tower as it is now configured — was the tallest building in St. Paul. The 417-foot, 32-story building was constructed in 1931 and competed with New York City's Empire State Building for construction materials.

The 16-story East tower, built in 1915, was originally known as the Merchants Bank Building before being enveloped in the First National Bank Building complex. The four-story North building was constructed in 1970.