[skookum]

> You haven't lost anything yet, as you haven't sold them.

That's not how it works. The difference between a realized loss and an unrealized loss is only tax consequences. If your shares have a book value of $1200 from when you bought them yesterday and a market value of $1000 right now, you could have bought the same number of shares today and had an additional $200 in cash. You're holding the same number of shares in both scenarios but your net worth is $200 lower if you bought yesterday. Obviously any dividends received since the time of purchase would change the net outcome.

The "you don't lose until you sell" meme is self-rationalization popular on reddit and in the Bitcoin community.

[taylodl]

This is why most people employ (often unwittingly) dollar cost averaging (DCA). I say often unwittingly because that's what you're actually doing when contributing to a 401K and for the non-expert investor, it's actually a decent investment strategy. What screws up the long-term benefits of DCA is if you go and start moving your money around after realizing a loss in a particular investment fund.