Doctrine of Merger
The duty to deliver marketable title is a contractual duty. The seller's contractual obligations ceased when Seller delivers a deed to Purchaser and Purchaser accepted it.
**Because of the merger doctrine, once the seller closes with the buyer by delivering a deed transferring title, the seller no longer has any obligations under the contract. Therefore, after that time, the buyer may not sue the seller based on the contract. The seller's rights, if any, arise solely under the deed. The only obligations the seller will then have from the particular transaction will arise from thewarranties, if any, the seller included in the deed.**