[raviolo]

Would creating, say, online marketplace to help people lose desired amount of money with certainty - for example, via some sort of specially crafted financial instrument - violate any applicable rules & regs? Idea for the next YC batch?

[PhantomGremlin]

You don't need to do anything special for this. I don't see the need for a startup to "help" with this. Existing options are already sufficient. It would take a financial professional less than a day to write up a comprehensive guide to such a strategy.

E.g. if you want to lose $5,000 just buy a bunch of options that are way out of the money, that have a perhaps 1% chance of paying off.

99% of the time you lose $5,000, which is what you wanted.

1% of the time you win $500,000, which is a nice problem to have. That payoff will probably dwarf the financial penalty of whatever discontinuity you were trying to work around.

[ahakki]

Charitable contributions can be deducted from taxable income in a lot of places.