Neither officials from Shorenstein nor Brookfield, the owner, would comment, saying it is policy not to discuss rumors. The 1.2-million-sf building stands 714 feet and was designed by Skidmore, Owings & Merrill.Earlier in the year, analysts confirmed that Toronto-based Brookfield planned to sell its non-core holdings, in places such as Denver and Minneapolis, to concentrate its portfolio in its core cities, such as New York, Toronto, Washington, DC and Boston.

At first Brookfield planned to sell all of its Downtown Denver holdings, but reportedly is now selling the buildings individually. Buyers other than Shorenstein are also lining up to purchase the two World Trade Center towers and its 50% ownership in the Colorado State Bank building, sources tell GlobeSt.com. Brookfield's entire portfolio in Denver covers 3.02 million sf, accounting for more than 10% of the entire Downtown Denver office market.

Chicago-based Equity Office Properties, which owns the Tabor Center, US Bank Tower, Dominion Plaza, 410 17th St. and the Denver Post Tower, made no secret that it would love to add Republic Plaza to its portfolio. One Denver developer tells GlobeSt.com that EOP could effectively increase all of its rents Downtown across the board by $1 per sf if it acquired Republic. By increasing its critical mass Downtown, it would give EOP more choices when accommodating tenants, as well as providing for more cost savings, the developer explains.

However, as a publicly traded REIT, it is difficult for EOP to meet the price being paid by a privately held company such as Shorenstein, brokers and others say. The word on the street is that Republic will obtain a cap rate of 6% or below, a number that REITs have trouble justifying.

Brookfield hired Steve Silk and Jay Borzi of Los Angeles-based Secured Capital to sell the property. Secured Capital, in turn, is working with Mike Winn and Tim Richey of Denver's Cushman & Wakefield office. None of the brokers on the deal would comment.

Shorenstein was founded in 1924 and since 1992 has sponsored seven closed-end real estate investment funds with an aggregate capital commitment of $2.3 billion. In February, it crated Shorenstein Realty Investors Seven LP with $775 million in equity, allowing it to purchase as much as $2.2 billion in real estate. It typically expects to buy buildings with 60% to 65% equity.

Shorenstein's properties, in addition to the John Hancock Center in Chicago, include the 500 West Monroe St. building and Prudential Plaza in Chicago; 1155 Perimeter Center West in Atlanta; 125 Park Ave. and the Starrett Lehigh Building in New York City; Oakland City Center in Oakland, CA; WebEx Tower, in Santa Clara, CA.; and Hamilton Square and 1111 Pennsylvania Ave, NW in Washington, DC. Its biggest concentration of buildings, however, is in its hometown of San Francisco. Its San Francisco portfolio includes the Russ Building, 1 California St., 50 California St., 45 Fremont St., 350 Bush St., 500 Pine St. and a parcel of land in Mission Bay.