Professionals are often wrong, and timing the market is more difficult than it might seem - in no small part because many investors are unable to prevent emotio

Professionals are often wrong, and timing the market is more difficult than it might seem - in no small part because many investors are unable to prevent emotions from affecting their trading decisions. That said, it's entirely possible that the market is irrationally high; the question then becomes how long it can remain that way. There's a famous Keynes quote - “The market can stay irrational a lot longer than you can stay solvent.” If you do think stocks are overpriced, it may be advisable to create a disciplined strategy for profit taking - selling a few percent of your net assets each time the market increases by, say, 10%.