Shortly after moving to Chicago, Les Atlass returned to the airwaves, and received a new license for a broadcasting station operated from his home at 7421 Sheridan Road, again with the call letters WBBM and transmitting on 1330 kHz, now with himself as the licensee.

In 1925, station ownership was transferred to the Atlass Investment Company, with the station located at 1554 Howard Street, now transmitting with 1,500 watts.
On June 4, 1925, studios and transmitter were moved to the Broadmoor Hotel in Chicago's Rogers Park neighborhood. "
95.99%" of the station's programming was devoted to music during this period, including live musical broadcasts aired from a small studio in the lobby of the hotel.
In 1926, the Stewart-Warner corporation leased the station's full schedule, and began producing all of its programming.

On June 15, 1927 WBBM moved to 770 kHz with 1,000 watts, sharing time with Chicago stations WAAF (now WNTD) and WJBT.
Later in the year power was increased to 5,000 watts.
On November 11, 1928, under the provisions of General Order 40, the Federal Radio Commission reallocated frequencies on the AM broadcasting band.
WAAF was reassigned to 920 kHz, while WBBM and WJBT remained at 770 kHz, with the frequency now designated a "clear channel" assignment.
WJBT's license was acquired by the Atlass Investment Company, and the two stations were consolidated as WBBM-WJBT, although the latter call sign was rarely, if ever, used.
Its transmitter was moved to Glenview, Illinois, and its studios were moved to the Wrigley Building.
Powers for clear channel stations could potentially be up to 50,000 watts, and WBBM's was increased to 10,000 watts in 1928 and 25,000 watts the following year.
Shortly after moving to Chicago, Les Atlass returned to the airwaves, and received a new license for a broadcasting station operated from his home at 7421 Sheridan Road, again with the call letters WBBM and transmitting on 1330 kHz, now with himself as the licensee.
In 1925, station ownership was transferred to the Atlass Investment Company, with the station located at 1554 Howard Street, now transmitting with 1,500 watts. On June 4, 1925, studios and transmitter were moved to the Broadmoor Hotel in Chicago's Rogers Park neighborhood. "95.99%" of the station's programming was devoted to music during this period, including live musical broadcasts aired from a small studio in the lobby of the hotel. In 1926, the Stewart-Warner corporation leased the station's full schedule, and began producing all of its programming.
On June 15, 1927 WBBM moved to 770 kHz with 1,000 watts, sharing time with Chicago stations WAAF (now WNTD) and WJBT. Later in the year power was increased to 5,000 watts. On November 11, 1928, under the provisions of General Order 40, the Federal Radio Commission reallocated frequencies on the AM broadcasting band. WAAF was reassigned to 920 kHz, while WBBM and WJBT remained at 770 kHz, with the frequency now designated a "clear channel" assignment. WJBT's license was acquired by the Atlass Investment Company, and the two stations were consolidated as WBBM-WJBT, although the latter call sign was rarely, if ever, used. Its transmitter was moved to Glenview, Illinois, and its studios were moved to the Wrigley Building. Powers for clear channel stations could potentially be up to 50,000 watts, and WBBM's was increased to 10,000 watts in 1928 and 25,000 watts the following year.
WBBM (AM)