What is the effective interest rate of a patent loan?

The effective interest rate for a patent loan will be in the neighborhood of mid- to high-teens.

In some cases, we can offer loans in the low-teens, but that is usually reserved for companies with especially good cash flow.

Please note that this rate is much lower than angel or venture equity, which is typically 50% or more. By taking a loan against the assets you already created, you can get much further without having the negative effects of selling your equity to investors.