system
Given the following post, respond as if you're commenting on Reddit:
human
[Death Note] With the exception of outright selling it, what would be the best way to make money with a Death Note?

Maybe shorting the stocks of  companies with famous CEOs and killing the CEOs causing the stock to go down? Companies unexpectdly losing their figure heads should take a hit.
gpt
In the anime, a board of directors of a corporation were using it to kill off competition and assist in corporate takeovers.

Holding people for ransom would be a great way to amass wealth though. All you need is a name and a picture and you can kill them whenever. Once it gets out that there is someone who can kill anytime, anywhere, then it's easy to demand money and it's easy to sell your services as a Assassin. You could literally hold a auction to kill a politician with options to buy votes that you could invest towards kill or not kill options. In the US at least, political parties are so polarized that there would be people of the opposite party perfectly willing to donate a few bucks to killing the opposition party's elected officials.