I have a series of annual employee stock option grants that were struck at varying prices over the course of several years, all of which have now vested. Some options are at this point worth a decent amount, some less so, and some are underwater. My goal is to rebalance my portfolio so that my investments are not so concentrated in my company's stock, so I wish to exercise and sell some options, and reinvest the proceeds in index funds. My question is, what should I consider when picking which of the grants to exercise and sell?
It seems to me there are two factors to consider, which are the expiration date of the grant as well as the outlook for the stock price. It may make sense to exercise the oldest grants first, since I could be forced to exercise at a less advantageous time if I still have them when the expiration date arrives in a few years. I'm also considering the future outlook for the stock - it seems if I expect the stock to continue to go up, I'd be best off exercising the grants with the lowest strike price, since the higher strike price options will see a larger percentage gain in value with each dollar of gain in stock price. On the other hand, if I expect the stock price to go down, I should exercise the grants with the highest strike price, since those are at higher risk of becoming worthless.
As a worked example, suppose I have an option grant struck at $100, another option grant struck at $110, and the current price is $120. I could exercise and sell 1 option of the $100 grant to cash out $20 to invest elsewhere, or 2 options of the $110 grant to achieve the same. If the stock price drops to $110, I'd have been better served by keeping the $100 grant, as I could still get $10 instead of $0. On the other hand, if the stock price rises to $130, I'd have been better off keeping the $110 grant, as I could get $40 for those two options instead of $30 from the single $100 option.
I'm trying to exercise at an advantageous time when the price seems high compared to its recent history, which seems to suggest that I don't have high confidence that the stock will continue to go up much. But at the same time, I'm doing this as a portfolio rebalancing without trying to get too into timing the market. Are there any other things to consider here?