You get your whole 401k but still gets taxed to high heavens if you withdraw it.

I quit the company and came back. They told me that since I had less than $1,000 with them then they reimbursed it to me. But I think if it is over that threshold they keep an account for you it just becomes a fidelity personal account

Worked in 401k; you will get all the employer contributions if you met the vesting schedule aka a certain amount of time with the company, this changes company to company. If your balance is below a certain threshold like the commenter above usually 5k or less they will make you remove your funds from their amount (they don’t want to pay for your account) roll it over or cash out. If you move it to another qualified account (ira or another 401k , you will not be taxed) if you cash out you will be taxed if your contributions were pretax. If your contributions were Roth (after tax) you will not be taxed when you take them out. Either way when you cash it out if you are under retirement age you will incur a 10% penalty.