(Not A Lawyer disclaimer) There's a tax law reason why this isn't a trivial change. Best reference I could find is here: https://thestartuplawblog.com/incenti

(Not A Lawyer disclaimer) There's a tax law reason why this isn't a trivial change. Best reference I could find is here: https://thestartuplawblog.com/incentive-stock-options-post-termination-service-exercise-periods/ https://thestartuplawblog.com/incentive-stock-options-post-t... In short, to be treated as an Incentive Stock Option - which comes with benefits for you (taxed as capital gains, not as income, if you hold 1 year from exercise and 2 years from grant) and for the company (different accounting treatment and they don't have to withhold taxes at exercise time) - the option must expire within 90 days after your employment. Some companies are now moving toward treating options as NSOs if you keep them after your employment, and ISOs if you exercise them during this period - but this kind of change comes with lawyers and accountants (and maybe even a change to the stock option plan approved by the board of directors) attached, so it's not easily negotiated for a single employee.