83(b) election

Founders of a C-Corporation usually receive stock that vests over time. Without an 83(b) election, each vesting can be taxed at the stock's value then. The election taxes the whole grant at its value on day one, which for a new company is close to nothing. It has to be filed within 30 days of the grant, on Form 15620. A founder with no SSN or ITIN writes "Applied For" and encloses a copy of a Form W-7 application.