He is the founder and CEO of Believe Group created in 2005. The group develops products and services for artists and labels under the Believe & TuneCore brands, while also developing specialized labels such as AllPoints, Naïve, MusiCast or SoulFood. Believe collaborates with many artists, who are served by 500 staff in 32 offices around the world. Denis started working in digital music in 2001 in the United States with MP3.com, eMusic and Rollingstone.com.
In September 2018, Believe acquired a 49% stake in French indie label Tôt ou tard from Wagram Music.
In October 2018, Believe acquired a majority stake in German label Nuclear Blast.