BB stocks are always harder to short, but I have entered shorts on most stocks like AIG or HEB. Sometimes I couldn't short stocks with huge floats like SIRI back when it was 9.00, and I had a hard time shorting TGEN in the past. And HEB was hard to short at 4.00.
But I think the biggest reason scam stocks are easier to pump higher is because of the shareholder base. Scam stocks all tend to have naive shareholders that didn't sell even when the stocks went to penny status. All sellers were out of the stock.
While "blue chip" companies all have a large base of sophisticated owners with large positions willing to take profits if the stock gets run up too high on hype, there are usually many analyst giving opinions, many sorts of option positions, many ways to hedge.
And if a stock is just getting discovered, like say ISRG years ago, then many take too large a position on margin in the stock, and they are easy to shake out by a sharp downturn. While no one wants to scare holders of a scam company into selling. We have all seen promising biotechs get a one day very hard dump right before great news.
BTW, I was always disappointed with INGN, they had great hype potential but they had that one very large pharma seller with a 5 million share block. INGN should have been easy to run to 20. )) Most scam companies don't have anyone with a large block that is selling.
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