Is my limit based on committed funds or notes purchased?

While your limit is technically based on notes purchased, you will be unable to commit funds towards the purchase of notes that exceed your investment limit. When a commitment is made, you are committing the funds towards the future purchase of a note, that is dependent upon the loan reaching its total funding amount. If you were to commit funds that exceeded your limit, and the loan reached its goal, the transaction wouldn't be able to take place. This is why you cannot commit funds that would cause you to be in excess of your investment limit.