Answer from Kyle, PHR:
Generally, and as long as you’re not a federal contractor, you don’t need to post an open position for all employees to see. That said, if your company has an established policy or practice of posting internally, you should be consistent.
Of course, what you can do as an employer and what you should do are often not the same. Posting new positions internally is generally a good idea, even if it creates some extra work. Opening the position to all internal applicants demonstrates transparency and increases the likelihood of finding the best candidate. The employee you had in mind might not actually be the best person for the job, they may not be interested in the position, or other circumstances might change such that having a wider applicant pool would be an advantage. Posting jobs internally also helps you keep a pulse on your internal talent pool and see who is interested in either cross training or promotional opportunities.
Note: This does not constitute legal advice and does not address state or local law. For example, Colorado does have posting requirements.
Kyle is a professional author, editor, and researcher specializing in workplace culture, retention strategies, and employee engagement. He has previously worked with book publishers, educational institutions, magazines, news and opinion websites, nationally-known business leaders, and non-profit organizations. He has a BA in English, an MA in philosophy, and a PHR certification.