Usually, I will only do an assignment of contract if my assignment fee is $3,000 or less.
When you start getting into profit margins of $5,000... $10,000... $15,000... your assignee may try to negotiate your fee down quite a bit, because they see that you are making "so much money" off of one wholesale deal. Of course, they don't think about the thousands of postcards you have sent out, all of the wild goose chases, and the 100+ calls you've had to screen just to get this one golden egg. They usually just see this as "one deal" and view you as taking advantage of them.
If the profit margin is above $3,000... I usually do what is called a double close. What you will need is "transactional funds." You can Google "Transactional Funds" and a whole slew of companies will come up that offer this service. Basically, you borrow the money for the same day of closing to purchase the property. You have a whole separate HUD sheet as if you purchased the property. Then you turn around and sell it to the end buyer and have yet another whole separate HUD sheet. This keeps your profit margins more private.
Usually, transactional funds will charge you 2 to 3 points on the total amount you are borrowing to buy it for. For example, if you were purchasing the property for $100,000 and selling it for $130,000... you would be charged 2 points... or $2,000 dollars for borrowing $100,000 to sell it for $130,000.
You don't need credit, employment or background check for transactional funds since you only borrow the money for one hour to sell it to an end buyer.
This is the best way to insure privacy on financial matters like this.