Duncan Mathison, an outplacement executive and co-author of the 2009 book “Unlock the Hidden Job Market,” told The Wall Street Journal he calculates that about 50% of positions are filled without a formal process.
It’s not illegal to forgo publicly posting an open position, though many HR departments require positions to be posted, even if the hiring manager already has a candidate in mind. This may protect companies from discrimination lawsuits. That doesn’t mean they’ll actually consider people who apply through that public listing.
Hiring managers don’t want to sift through a big pile of résumés, or they’re vaguely thinking about creating a new position and when they hear about a great candidate, get it created right away for the person. Or they just hire internally by promoting someone or pulling them from another department.