Fascinatingly to me, even though I understand work-made-for-hire law, the interplay between copyright ownership and employment status had not really occurred to me as it pertains to labor law until researching this article.
Under current copyright law, a publisher can only own a work if it is created by an employee or made pursuant to a work-made-for-hire agreement (see this post for a more detailed discussion of work-made-for-hire). If the creator was not an employee and if there was no contract, then the creator retains ownership. If there is a contract but the work does not fall into one of the enumerated work-made-for-hire categories (see here), then the creator retains the rights. The creator can assign ownership to the publisher, but the original creator would retain the right to terminate the transfer later—a proposition most publisher’s would like to avoid (see my posts on the rights to Superman, Captain America, etc.).
The above seems straightforward, but it can get complicated. For instance, the analysis becomes murkier when applied to independent contractors. Even though they may be classified as an independent contractor, if the relationship with the employer meets the criteria for a common law agency relationship as set forth in Community for Creative Non-Violence v. Reid (see my first post on forming a comic book union), then it is possible for the created work to be deemed a work-made-for-hire.
For instance, one of the reasons the Kirby estate’s challenge to reclaim ownership over the Marvel characters he created failed was because the appellate court, in applying an older test to determine work-made-for-hire, ruled him to be an employee for purposes of copyright ownership. Granted, that was applying an older copyright law, but it makes for a fascinating “What if” scenario today. If the case hadn’t settled before it reached the Supreme Court, the outcome may have been very different.
Finally, this split in wanting to own the intellectual property outright versus the desire to classify workers as independent contractors played a key role in the formation of the Writers Guild in the 1930s and 1940s. The studios were arguing on one hand that the writers were employees within the meaning of the 1909 Copyright Act so that the studios would own the copyrighted instead of the writers, and on the other hand, the studios were also arguing the writers couldn’t unionize because they were independent contractors.
Even though copyright law and employment law are two very distinct practice areas, they do overlap when it comes to work-made-for-hire. Generally speaking, just because someone is deemed an employee for copyright purposes does not mean they are an employee for labor law purposes. However, California takes the view that an employer cannot benefit from a contractual work-made-for-hire provision without also being considered the employer. Knowing your employment status, and what your agreements say, is very important.
 See Fisk, Catherine, (2018) “Hollywood Writers and the Gig Economy,” University of Chicago Legal Forum: Vol. 2017, Article 9. Available at: https://chicagounbound.uchicago.edu/uclf/vol2017/iss1/8
 Id., at 184-185.