How often is IRS or State advised of a new job?

Does the IRS or CA State receive notification that you have a new job? Is it only once a year when your employer files your W2 or is it more frequent?

Public Comments

Typically, if the new employer exceeds a certain size, they must file a W4 form as part of your employment paperwork. As soon as that W4 gets mailed, THAT's when the IRS finds out about it. State usually finds out when a state withholding tax is filed on your behalf from a new funding source and the older source dries up.
They are notified by the W2 but also keep up-to-date every time you're paid and taxes are withheld.
when ever you apply for a job you fill out a W4
In Michigan, there is a new hire form that has to get filed with the unemployment agency - so when you get a new job, the State of Michigan is notified. Not sure if that is part of the new coordinated child support changes and applies to all states or only Michigan or if it depends on the state... W-4's are not filed with the IRS. The employer keeps them for their records and has to make them available if the IRS decides to audit them. I have never heard of a W-4 audit by the IRS. The only federal audits I have heard of are I-9 inspections by INS. So, IRS is only informed of a new job when they receive the W-2 at year end. The IRS only gets tax information for employees at year end when W-2's are filed. They get paid withholding taxes on a weekly, monthly or quarterly basis by the employers, but do not get specifics as to how much a particular employee paid until the W-2's are processed.
Employers have to notify the state employment tax departments shortly after a new hire for the purpose of child support enforcement. IRS gets its information from W-2 filings.