The one question in my mind the whole time which the article doesn't answer, is if you exercise options and buy unregistered stock with has a current FMV in excess of the strike price--a taxable gain--but then within the 5 year deferral period the company dissolves in a puff of smoke, making the stock you hold actually worthless... do you still owe the tax?
Seems to me that a key advantage of the deferral period would be if it allowed one to net out the true capital gain/loss if you actually sold or otherwise disposed of (e.g. it became worthless) the stock within the deferral period.
This is definitely much more preferable to the typical 90 day window + pay the tax this year scenario. Even if the company does not go public, the employee at least now has five years to come up with the money to pay the tax bill. If you are fortunate enough to work at a company that offers a longer exercise period (e.g., Quora and Pinterest are two I can think of offhand that offer 7+ years to exercise your options), then you've got over a decade of time--unless I'm misunderstanding the bill.
Is it possible to "un-exercise" your ISOs? If so, that also gives employees five more years to watch the company trajectory and make a more informed and measured decision -- if they lose confidence in the company, they can return the ISOs to the employer instead of paying an upfront tax bill on what is still somewhat of a lottery ticket.
Seems to me that a key advantage of the deferral period would be if it allowed one to net out the true capital gain/loss if you actually sold or otherwise disposed of (e.g. it became worthless) the stock within the deferral period.