What if you sell a $500K property and do a Seller Finance Deal and only get $100K(20%) down.... How does 1031 work with that?

When I identify 3 properties as replacement properties, do I need to put them all under contract? If I put them all under contract, should I include a contingency (1031 exchange) since I won't be able to buy all 3?

Thanks for the info!

Thank you

Thank you!

Thanks!!