There was an user (ipohmali) who would call the HR of your current company to do a background check.. and of course, informing your HR that you are looking for a new job.

Be careful of companies as such.

Ya, though most of his advice was nonsense - he was a good at keeping the “jobs and career” segment alive.

Hi, what if I wish to set-up a startup company, and I wish to keep it as a secret from my employer? The startup company does not operate in the same field as my employer company, so there is no conflict of interest. It is required for all employee to disclose any side business to the company though, but I would like to keep it as a secret, would like to keep a very low profile and also wouldn't like to answer any question.

Can the employer check if I am the shareholder of any company or if I own any company through any channel?