Section 3 of Michigan's Unclaimed Property Act states that all property held unclaimed for more than 5 years is presumed abandoned. Section 4 of the Act presumes property to be abandoned if one of the following requiremets are met..."(c)The records of the holder do not reflect the last known address of the apparent owner, and 1 of the following is established: (i) That the last know address of the person entitled to the property is in this state."

At mortgage closing, an escrow account may be set up for the seller of property until work/repairs are completed. My question is this: If the seller does not claim the funds, can we assume their last know address is Michigan based on the purchase agreement or HUD? We have no reason to maintain a sellers address. The funds are held in a Bank DDA.

I believe you can make that assumption. At closing, you're collecting their address for year-end tax reporting - that is most likely the last address you'll ever get for the seller. (Hard to believe a seller would leave those dollars on the table...)