Chicago, at first dubbed The Chicago Transit Authority, immediately stood out due to their unique, horn-driven instrumentation and top-notch songwriting, a combination that quickly found a home on free-form FM radio in the late '60s. According to Billboard, Chicago was the leading US singles charting group during the 1970s. They have sold over 40 million units in the US, with 23 gold, 18 platinum, and 8 multi-platinum albums. Over the course of their career they have had five number-one albums and 21 top-ten singles.
Over the course of its career, the band REO Speedwagon has sold more than 40 million records and has charted thirteen Top 40 hits, including the number ones "Keep On Loving You" and "Can't Fight This Feeling". REO Speedwagon's mainstream popularity dissipated in the 1990s but the band remains a popular live act.