A federal judge has ruled that DC Comics holds the rights to Superboy and the 1938 advertisements that marked the first published appearances of Superman, rejecting efforts by the heirs to one of the Man of Steel’s co-creators to reclaim the works.

U.S. District Judge Otis Wright granted summary judgment to DC, a unit of Warner Bros., ruling that a 2001 agreement that the heirs to co-creator Jerome Siegel made with the studio encompassed the rights to Superboy and the advertisements.

Siegel and co-creator Joseph Shuster sold the rights to Superman to DC Comics for $130 in 1938, but their heirs have attempted to exercise a provision of the Copyright Act of 1976 that gives authors and artists the ability to reclaim works in a certain window of time many years after they signed away their creations.

Even though the Siegel heirs attempted to “terminate” the rights to Superman in 1997, the 9th Circuit held that settlement talks with DC Comics in 2001 produced an enforceable agreement that again granted the studio rights to the character. Nevertheless, a question remained as to whether that meant that DC also owned the rights to Superboy. Siegel first proposed the idea for a young Man of Steel in 1938, and DC Comics later published the first Superboy comic without his consent. Also in dispute was who owned the rights to black-and-white ads that ran in 1938 previewing Action Comics No. 1.

The intent of the “rights termination” provision of the Copyright Act is to give authors and their heirs a second shot at reclaiming their creations, or additional leverage to strike better deals than they could earlier in their careers.

A federal judge in 2008 ruled that the Siegel’s 1997 termination notice did not encompass Superboy and the ads, but Wright wrote that the Siegels “undoubtedly intended” those works to be included. As such, they “used that termination as leverage” to negotiate the 2001 agreement, which included a $2 million advance, a $1 million signing bonus and a guarantee of $500,000 per year for 10 years, Wright wrote.

The Siegel heirs have contested that the 2001 agreement was an enforceable pact, but a draft that Siegel’s widow Joanne later rejected. And Wright suggested that the litigation will continue in state court, possibly over the Siegel heirs’ contention that DC didn’t honor the 2001 agreement’s terms. The heirs to Shuster, seeking to reclaim their share of the Man of Steel, are appealing Wright’s decision last year favoring DC.

In the meantime, Wright seemed relieved to declare that his portion of the case, what he called “this litigation of superhero proportions,” has drawn to a close.