CHICAGO (CBS) — The Wrigley gum company announced Thursday that it will be leaving the iconic Wrigley Building on the Magnificent Mile.

But the company will be staying in Chicago. It is moving its operations to its campus on Goose Island.

Currently, the 90-year-old Wrigley Building at 410 N. Michigan Ave. houses about 250 Wm. Wrigley Jr. Co. staff members in Chicago. When the company moves those employees at the end of next year, it will bring the total number working on the Goose Island campus to 600, the company said.

Wrigley has already had a presence on Goose Island for several years.

The Wrigley Global Innovation Center at 1132 W. Blackhawk St. has been open since 2009. Nearby are the Engineering and Information technology centers, which in total gives Wrigley more than 360,000 square feet of office and lab space on Goose Island.

Wrigley also has office space at 600 W. Chicago Ave., the former Montgomery Ward catalog building that is now best known as the home of Groupon and several tech firms.

As for the Wrigley Building, the company says it will seek “new development opportunities.” The Chicago Tribune points out that the building is currently at 60 percent occupancy with Wrigley, but occupancy will drop to 35 percent once Wrigley moves out.

The company said in a news release that the “once state-of-the-art interior” at the Wrigley Building is in need of “substantial modernization” to attract future tenants.

While Wrigley is considering forming a joint venture to take over the building, or even selling it, the company does not plan to take its name off the building, the Tribune reported.

The site of the building was chosen personally by gum magnate William Wrigley Jr. Its two towers were constructed between 1920 and 1924, and the walkway that connects them followed in 1931. Patterned in a French Renaissance style, the building is clad in about a quarter million terra cotta tiles and features one of the city’s most iconic clocks.

In addition to Wrigley, the building is home to ad agencies, marketing firms, and investment management companies, as well as the consulate-generals of Austria, Ireland and the United Kingdom.

The Wrigley Building was also home to what we now call WBBM Newsradio 780 from 1929 until 1956, and to CBS 2 from its inception in 1953 until 1956, when both stations moved to the longtime CBS Chicago headquarters at 630 N. McClurg Ct.