It is NOT normal for truly experienced business brokers. Selling a business is not that black and white. This hurts the seller, who will most likely never sell their business.

The broker who asks for "proof of funds" is just trying to cash out. In most of their NDA's they state that they have not even verified the business data. When they ask me for "proof of funds", I ask for "Proof of Financial Data."

Really, I just move on to the next acquisition target. Remember, there are plenty of small businesses you can ethically acquire without a broker and let the seller keep that broker fee they would have paid.