[quote name='Wombat']Sort of, Capt Marvel was created by Fawcett comics (which is why Capt Marvel lives in Fawcett city) and was sued by DC for being Superman clone. DC eventually bought the rights to the character but can only use the name Capt Marvel when in the comics, outside of comics he is Shazam[/quote]In the 1940s, Captain Marvel was actually more popular than Superman. As you note, DC sued Fawcett, and eventually obtained the rights to the character. Decades later, Marvel comics sued for the trademark rights to the name "Captain Marvel," and won (there is a Marvel Comics superhero called "Captain Marvel," though usually spelled "Mar-vell"). So, while the character is still Captain Marvel, no marketing material may use that name, so when Captain Marvel has had a solo comic published by DC the title has been some variation of "Shazam" (Power of Shazam, etc.).
On a tangental note, DC no longer owes the IP rights to "Superboy," so that name and basic character have been "ret-conned" out of the DC universe. Early adventures of Superman now make reference to "Young Superman."