I buy, it drops. I sell, it bounces. Why?
Plenty of people have had this feeling. It deserves to be taken seriously, without turning it into a law: not everyone buys at the top or sells at the bottom, and nobody is personally cursed. But several well-documented biases make those bad moments more tempting than they should be. Market regulators describe them too, for example the UK's FCA and Spain's CNMV.
FOMO, the fear of missing the start
You wait for it to rise before you feel reassured. Except the more it rises, the more obvious buying looks, and the higher the price you pay.
You hesitate when bitcoin is at $60,000. You make up your mind at $75,000, because "this time, it's taking off".
Individual investors buy more of what grabs their attention: stocks in the news or that just moved sharply (Barber and Odean, 2008).
The herd effect
When everyone around you talks about Bitcoin, general enthusiasm starts to look like proof. Yet a hundred people copying each other don't bring a hundred pieces of information.
Three friends have bought, your feed talks about nothing else, and the echo ends up sounding like certainty.
People can follow others while setting their own information aside, and these crowd movements can reverse abruptly (Bikhchandani, Hirshleifer and Welch, 1992).
Recency bias
The move of the last few weeks ends up looking like tomorrow's direction. After three months of gains, gains feel normal. After three months of losses, the fall feels endless.
"It's up 30% in a month, it'll keep going." Or the opposite, with exactly the same confidence.
Across nearly fifty years of surveys, investors' return expectations rise after market gains and fall after declines (Greenwood and Shleifer, 2014).
Loss aversion
Losing hurts more than winning feels good. A 20% drop can become hard to bear, even if you knew it could happen.
You planned to hold your bitcoin for five years. By the third day in the red, you don't dare open the app anymore.
Nuance: this bias doesn't always lead to panic selling. It can also do the opposite, pushing people to hold a losing position too long so the loss doesn't "become real". That's the disposition effect: selling winners too early, riding losers too long (Shefrin and Statman, 1985; Odean, 1998, based on the accounts of 10,000 individual investors).
Confirmation bias
Once you've taken a position, you mostly look for what proves you right. Opposing views seem less serious, good news more solid.
You read to the end the article predicting a rise, and skim the one about the risks.
A bias found in many fields, well beyond finance (Nickerson, 1998).
Deceptive hindsight
Afterwards, a peak looks obvious. At the time, nobody knew it was one. Hindsight bias makes us feel we could have predicted it, and therefore that we'll predict the next one.
"Everyone could see it was too high." Everyone, really?
Knowing how a story ends makes us overestimate how predictable it was (Fischhoff, 1975).
Selective memory
Some decisions stay etched in memory: the sale right before a rally, the purchase right before a crash. They come to mind more easily than ordinary decisions, and we end up believing they sum up the way we invest.
A single bad sale can be enough to make you doubt your whole plan, years later.
What comes to mind easily seems more frequent (Tversky and Kahneman, 1974). Lived experiences also shape our appetite for risk, sometimes decades later (Malmendier and Nagel, 2011). I cover this from another angle in Beware of your past experiences.