I have only (knowingly!) met one high end conman aiming to take - at current prices - tens of millions out of companies. It was around 1980 and he had 'invented' a new storage device based on analog technology which therefore did not have the same limitations as digital. One 'cell', being analog, could hold as many 'digits' as you wished: instead of 1 and 0 it could hold, say, 1.101110111011. Consequently whichever company gained the exclusive rights to manufacture this held the monopoly on the entire storage demand for the world.

In principle this could work. In practice, it is limited by the ability of A/D and D/A converters and the need for perfect repeatability - read that previous number back as 1.101110111001 and you do not have effective storage.

Nevertheless, the cost of NOT winning these rights, if they really existed, was as crucial as the cost of winning them, so both the specialist press and a number of companies took it very seriously indeed. I was one of about a dozen people in my company charged with assessing whether there was anything in it - he would not allow anyone to actually see or use the device, of course.