greenmail (GREEN-mayl) noun

The practice of buying a large quantity of a company's stock as a hostile
takeover measure, and then selling it to the company at a higher price.

[From green (money) + mail (as in blackmail).]

How did everyone else react to Anu’s colourful language yesterday? I just don’t buy this one.

Greenmail to me signifies coercion of corporate will by the impact of ecological pressure – it stands in the ranks of green~ words referring to ecological matters, with the obvious suffix from analogy with blackmail. An example would be when Shell were forced to cease their planned scuppering of the Piper Alpha drilling platform in the north sea, due to the popular outrage stirred up by Greenpeace.

Greenmail in the sense Anu found can only work, after all, in the USA which as far as I know is about the only country in the world to use the same colour for all its banknotes (whatever their value) and thus have gained some sense of, er, currency for the link of money and colour.