The one exception for me was a warrant. I had a very good understanding of how the warrant traded and what it was worth. There were also option on that stock. I was a market maker in the option. I looked to buy the warrant, which was OTM, for a discount to options with a similar strike price but less time to expiration. Warrants are almost always worth more as they often can't be shorted. I put large bids out below the market and waited for block trades where the seller looked to be either in liquidation or wanted a tax loss. I once bought 25,000 shares at $0.40 and 10,000 at $0.35. I valued the warrant at $0.65. I did not hedge it right away as the options did not trade every day. Before 30 days were up, the stock jumped and I sold the warrant for an average of $2.50. It traded up to $4.00.
Better to be lucky than good!