Complex sentence: Atticus is a brand of clothing founded in 2001 by Tom DeLonge and Mark Hoppus, however both Hoppus and DeLonge have sold their shares of the brand due to the break up of blink-182.
Split into simpler sentences: Atticus is a brand of clothing founded in 2001 by Tom DeLonge and Mark Hoppus. However, both Hoppus and DeLonge have since sold their shares of the brand due to the break up of blink-182.