The tallest building in downtown Spokane is going up for sale.

The Bank of America Financial Center, a 288-foot-tall office tower built in 1981 at Riverside Avenue and Howard Street, was listed for sale Wednesday morning, according to Jason Rosauer, senior vice president and partner with Seattle real estate company Kidder Mathews, which represents the building’s owner, Unico Properties.

“We’re in the market unpriced,” Rosauer said. “We’re expecting to see offers north of $55 million, yielding an investment return of over 7 percent.”

The sale includes the 20-story building at 601 W. Riverside Ave. and an eight-floor parking garage connected to it by a skywalk to its south. The main building has 330,000 square feet of office space. The property was most recently assessed at $38.2 million, according to county parcel data.

Unico Properties, a Seattle-based real estate company founded in 1953, purchased the building for $36 million in 2007.

Unico purchased the Spokane office building from First States Investors 5000A LLC, a firm then in Jenkintown, Pennsylvania, which in 2003 paid $40.8 million for it in a deal involving a portfolio of properties nationwide. Bank of America owned it before that sale.

The building site has a storied place in Spokane banking history. Shortly after the Great Fire of 1889, a five-story building was built there for the Traders National Bank. In 1914, the bank merged with Spokane and Eastern Trust Co.; in 1931, the old bank was demolished for a new seven-story Art Deco building, which The Spokesman-Review called “one of the most distinctive buildings in the Northwest.”

During the depths of the Great Depression, Spokane and Eastern Trust had merged with Seattle-First National, but retained its name in Spokane. The modern 20-story Seafirst Financial Center was built on the site in 1980, and the name changed to Bank of America Financial Center in 2000 following a 1998 merger.

Rosauer referred to the sale as an “investment sale, not a user sale,” and said the building’s tenants would likely remain the same.

“Our tenants are very valuable in that building. They’re our lifeblood in that building. Our tenants will not be disturbed,” Rosauer said. Current tenants include Merrill Lynch, Moss Adams, Bank of America and Clearwater Paper.

Rosauer would not share the building’s vacancy rate, but said it is “performing at or above market vacancy rates.” He said he already was fielding questions about the sale, but he was confident the sale would be complete by the fall.

“The building’s in phenomenal shape. It’s well located. The underlying message is it can compete with any building in the downtown market,” Rosauer said. “It’s where conservative capital can invest with a healthy return. It’s a stable investment.”

Alongside Rosauer, the investment brokerage team at Kidder Mathews representing Unico are Andy Miller, senior vice president and partner, and Rob Anderson, first vice president and partner.