The 60-Day Rollover Rule
If an eligible distribution from a retirement plan or IRA is paid directly to you rather than moved directly to another eligible account, you generally have 60 days from the date you receive it to complete a rollover. The IRS may waive the 60-day requirement in certain circumstances.
If you miss the 60-day deadline and no waiver applies, any taxable amount that is not rolled over generally must be included in income for that year. If you are under age 59½, the taxable amount may also be subject to the 10% additional tax on early distributions unless an exception applies.
A direct rollover can avoid the withholding and redeposit issues above. With a direct rollover from an employer plan, the plan pays the receiving plan or IRA directly. Mandatory 20% withholding generally does not apply, and you do not have to redeposit the funds within 60 days.
Statutory Citation: IRS.gov — Rollovers of Plan and IRA Distributions