over the past 18 months, I took about half a dozen 30% + losses on stocks, some of them I still own them and am down 60% + on them. Each position was less than 3% of account and that's part of the reason I extended my stay way beyond what I used to consider reasonable. But had the positions been larger I would have been annihilated even by getting out much earlier that is when I could have done it because most of them lost 30 % or more in one day.
There were MTL, Smith&Wesson, MELI, GNA, and others I don't even remember.
Most of the stocks had top IBD fundamental ratings and were bought for technical reasons with larger stops to account for the new volatility (not with the IBD method which doesn't really work IMO ). Then I made the mistake on some to wait for a double down entry to get out even, it never happened as I couldn't double dow except for one or two and it made the loss even larger of course. The real mistake was to get into stocks in the first place at this point of the cycle but then again there were so many huge moves as well.
I will never touch an individual stock again if not part of a basket that in itself is no more than 5-10% of portfolio. I have come to the conclusion that there is no money to be made in picking stocks outside of a very large portfolio which is impossible to monitor for short term technical moves (that is you have to be a fundamentals guy). You make some you give some and spend an awful lot of time looking for stocks. Any meaningful position such as recommended by the IBD or the Darvas method puts you at risk of an instant blowup. It is gambling. So if you are good gambler perhaps you can try to be the next Darvas or Zanger otherwise it is best to do something else.