The Burnside Bridgehead's tallest tower -- and possibly its most controversial -- has sold for $126.68 million.

The sale of the 21-story Yard building marks the city core's largest apartment transaction to date, according to a statement from commercial real estate brokerage Marcus & Millichap.

It also sets a new "high-water mark" for price per unit and price per square foot for Portland's east side, the firm said. The building houses 284 units, averaging 682 square feet.

Key Development, of Hood River, has sold the tower to Land and Houses, an offshoot of Bangkok-based investment firm Land and Houses Public Company Limited of Thailand. The purchase is the company's first acquisition in Portland.

Key bought the site from the Portland Development Commission for $1.5 million about three years ago.

With west-side towers like Park Avenue West and NV Portland also reaching completion this year, the Yard isn't likely to hold the largest apartment transaction title for long.

The sale of the Yard comes after controversy dogged its construction. The city overlooked changes to the architect's plan for the building, and issued the building permit anyway. Though the developer agreed to add windows, the result is a darker tower.

Meanwhile, a Portland building inspector came under investigation for conflict of interest after she admitted selling engineering software to contractors on buildings she helped approve, including the Yard project.

In September, two months after the tower opened, Willamette Week reported that the entire 11th floor was available to rent for $7,215 a night via online marketplaces like Airbnb and Vacasa.

The report came after city officials praised the Yard's developers for helping with Portland's affordable housing crisis.

In exchange for 10 years of property tax breaks from the city, the Yard has set aside 57 of the 284 units for those making 60 percent of the area's median income.

According to Yard's website, units are still available for rent. Ground-floor retailers include Tilt, a restaurant and bar, and Knot Springs, a wellness club and spa.

-- Anna Marum

amarum@oregonian.com

503-294-5911

@annamarum