Developer Michael Joseph has put the historic Dun Building in downtown Buffalo, the Caldwell Building in the Village of Williamsville and a third building on Delaware Avenue in Buffalo up for sale, as he seeks to shift his investments toward senior housing.

Joseph, founder and president of Clover Management in Clarence, is seeking bidders on the three buildings as either a package or individually, according to brokerage firm CBRE, which is representing him in the effort. Broker Robert Roller of CBRE has issued a “call for offers” on the buildings by Wednesday.

CBRE has been marketing the buildings for three months, but while it has “had a lot of people through the buildings,” no one has submitted an offer, Joseph said.

However, he said, it’s not a fire sale, and he is under no pressure to unload them, nor would he put them back on the market in a few months. “If the offers come in at numbers I like, I’ll sell the three buildings. If not, I’ll keep them,” he said. “They’re all fully occupied buildings.”

The sale is part of a strategy for Joseph over the past five years of selling his nonresidential properties to focus on senior housing and apartments.

He previously sold the Triad Building on Millersport Highway, an apartment building primarily for University at Buffalo students. Joseph owns several other prominent properties in the area, including the Ansonia Center at Main and Tupper streets in Buffalo, and the Delaware Franklin Building at the corner of Delaware Avenue and Allen Street, also in Buffalo. He said he expects to sell them over the next five years.

“This is just a continuation of what I’ve been doing in the last five years,” he said. “It is my intention in five years that Clover Management will be a senior apartment owner, operator and developer, all over the country. That’s really what we’re doing.”

Built in 1895, the Dun Building was the city’s first high-rise, the first steel-framed structure in the city and the first fireproof building. Named for financial services firm R.G. Dun & Co., a predecessor to Dun & Bradstreet Co., the 10-story building at 110 Pearl St. has 27,265 square feet of Class B office space and is fully occupied.

The building’s annual net operating income is $126,400, according to the marketing brochure for it. Joseph is seeking $1.58 million.

The Caldwell Building, at 5820 Main St., has 27,984 square feet of Class B space, and Joseph is seeking $2.8 million for the professional office building, which is 94 percent occupied. Its net operating income is $224,000 a year.

The third building, 3407 Delaware Ave., is a two-story commercial strip building in the Town of Tonawanda with 16,088 square feet of space, two blocks south of Sheridan Drive.

Joseph, a Williamsville native, spent six years as an investment banker in real estate finance on Wall Street in the 1980s before starting his real estate firm in New York City in 1987 and then moving it to Buffalo.

The firm has built 10 senior apartment projects so far in Western New York; two in Syracuse; one in Binghamton; one in the Utica suburb of New Hartford; one in Erie, Pa.; and one in Scranton, Pa., for a total of nearly 3,000 senior units.

Clover is breaking ground on projects in Oklahoma City, Kansas City and Cleveland, as well in Pennsylvania, and it’s moving into Connecticut as well. With about 120 to 125 units per complex, and eight to 10 projects planned for next year, Joseph said he expects to add about 1,000 senior units in 2013.

“It’s nice to have a demand that exceeds supply dramatically. You don’t see that often, so when you find it, you go for it,” he said. “It’s nice when you find a product that you can make money on and it serves a purpose and helps people.”