Thread by @investing_city

Looking through the last 5 years of my trading activity to find lessons from the many mistakes I've made.

Disclaimers:
- some of this is "resulting" but I still think it is useful
- no positions in any of the stocks below

[THREAD]

1/ In 2015, selling $VEEV at $25/share. Today it is $166.

I thought the market was too small, it was just $CRM for life-sciences.

Lesson #1: Don't under-estimate optionality.

2/ Bought $GPRO at $30.

Today it is at $5.4

"Hey, look it is down 60% from its high, must be cheap."

Lesson #2: Don't anchor to a 52-week high to determine if something is cheap or not. Especially when the market is trending up.

3/ Bought $GILD at $118. Today it is $69.

Low PE-ratio = good, right? You likely won't find a "cheap" business in plain sight in a bull market. I under-estimated the decline of its Hep business

Lesson #3: Find out why something is cheap & why you don't believe it's a problem

4/ Buying $MELI at $100 and selling at $250. Today it's at $627

This is probably my biggest re-occurring mistake. Selling winners.

The problem is figuring out what the opportunity cost was. Maybe it worked out? Still...

Lesson #4: Be very hesitant to sell greatness.

5/ Falling into the same bucket.
Buying $SHOP at $30 and selling at $150.
Today it is at $312

Buying $NVDA at $28 and selling at $40.
Today it is at $162

Lesson #4b: Don't be afraid to re-evaluate a stock you've sold even though it has gone up. This is tough but do-able.

6/ Used a limit buy with $NFLX at $75. Lowest it got was $77.

Today it is $375.

Lesson #5: Don't pinch pennies and dollars if you're playing the long game. By trying to save $2, I lost out on $298.

7/ Bought $PI at $50 and sold at $25.

Today it is at $31.

The company sells IoT endpoints to big retail players among other customers.

Lesson #6: Beware of customer concentration and long sales lead times. A brutal combo.

8/ Bought $TLND at $56 and sold at $35

Today it's at $37

The company kept boasting abt 100% growth in its new cloud segment but never broke out exact #'s. Ended up being smaller than management led investors to believe.

Lesson #7: Beware of an untransparent revenue break-out

/Fin

Again, I know this is "resulting" but the price of a stock has truth in it over time.

For example, maybe $PI or $TLND will go on to do well but in that case, my new mistake will be not having enough patience.

- What's your biggest investing mistake?