In a rare downtown offering, a 32-story boutique office building at 55 Broadway is on the market with pricing expected to reach around $140 million — or $375 a square foot.

Douglas Harmon and Adam Spies of Eastdil Secured will market the building for Broad Street Development, which is open to either a recapitalization or a full sale, The Post has learned.

The parties declined to comment.

Designed by FXFowle Architects and developed by Howard Ronson in 1983, the Broad Street-owned building was purchased in 2006 from the Bank of Communications for $82 million when it was 65 percent leased. It is now 98 percent leased with a variety of financial tenants.

Its 11,000 square-foot floors currently command rental prices in the low $40s per square foot and even lower floors have dramatic harbor views.

The tower, which has alternating horizontal bands of windows and rosy granite, is set back on a glass base in a plaza.

City permission has been obtained to further enclose 2,600 square feet for a large retail space.