When the tax bill was still pending, I recall reading somewhere that the bill changed capital gains tax so that instead of using the cost-basis for the stock in question you used a first-in first-out strategy so that the oldest cost-basis is the one use when selling.
I haven't been able to find anything that says whether this made it into the final law or not however. Does it still matter which stock you sell or is the cost basis used always the oldest under the new tax law?