It's not that Apple is unsound. It's that you picked ONE company. If you had said 100 years ago that you would trust not the long term viability of stock in the Pennsylvania Railroad Company (it paid out annual dividends for over 100 years unbroken), people at that time would have called you certifiably insane. Then history unfolded. Will Apple be around in 50 years? 10 years? It's an unfolding probability. Will you correctly get out and find the next such company in a manner that beats low cost passive diversified indexing? Doubtful.