Ask for proof of funds letter from potential cash buyers?

[Bradley White]

Ok, so I've built up a solid list of cash buyers. As a bird dog or wholesaler of apartments, would I be able to ask my cash buyers to send me a Proof of Funds letter or bank statement so I can have them on file? So when motivated sellers call me and I tell them upfront that I'm not the end buyer, I can still show the seller that I'm legit by having my investor's POF?