Why is it phrased as 1/48 of my (say) 48000 optipns/shares vest rather than a fixed amount of 1000 options/shares are awarded every month?

Alternatively, why aren't salary offers phrased as "you will get $640,000, which vests at 1/48 per month"? (Usually you'll hear "your salary is $160,000 per year and we do payroll monthly.)

Because when the four years are up, you don't automatically keep getting more options.

I don't understand. The alternative, as I detailed above, is "you get 1000 options per month for the next four years", which is also time-limited.

It's much easier on the accountants and the share spreadsheets to just assign you 48000 shares and make up funny 'vesting' rules than to update the spreadsheet every month to add 1000 shares for you. It's literally just ease of bookkeeping.

When the accounting and law professions catch up with the tech I think we'll see this all being much simpler, as with government and driving licenses and all the other pointless bureaucracy. But judging by how slowly bureaucracy moves, don't hold your breath.

When a company issues an employee an option at below its fair market value, it has literally created income for the employee, not in a funny accounting sense but in reality.

Replacing vesting with options artificially discounted to the FMV of the company at hire might not be different fundamentally from vesting, but it seems like there's lots of ways to abuse the capability of issuing discounted options.

When an option vests today with a fair market value from four years ago, the company has "literally created income" for the employee. But for whatever reason, this isn't a taxable event. I was inquiring as to the reason for this difference in treatment.

Options at the money are also incredibly valuable, and even more so when they're for a startup (hence their usage in compensation). It's instructive to look at the prices for at-the-money options on, say, GOOG 1--2 years out to see how much they're worth on the open market (easily 10% of the current stock price).