My standard advice is never average down. Certainly that's true with a penny or an OTC stock that's failing to deliver. There's nothing more dangerous than averaging down on a scam. I've seen investors go bankrupt doing that. Full blown scams are very rare on the NYSE, but we all remember the likes of Enron.
Even with NYSE stocks like DDD I don't average down unless perhaps the drop is caused by broad market weakness (as in 2009), and not by the investment's own shortcomings.
There are about 3,000 decent quality America stocks, plus tons of ETFs, CEF and mutual funds. If you're disappointed in 3D, I wouldn't recommend buying more.
As for SELLING what you still have, I'd base that decision more on your tax situation. I tend to harvest tax losses quickly.
Is 3D a dying stock or one that's temporarily depressed and likely to rebound? That's a very difficult call to make. And most flippers get such decisions wrong.
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