What's fair? Seller is requesting for non-refundable deposit...

[Riki Tang]

Here is the summary; I am a commercial real estate agent in San Francisco where we are currently in contract ( CAR standard commercial property for sale purchase contract) and I represent both the buyer and seller for a commercial property in San Francisco. Due diligence period (60) days will soon expire in 2 weeks, but due to the uncertainties of virus containment and shelter in place mandates, buyer is now asking for additional (90) days extension in hopes this virus outbreak will subside and then ready to move forward with deal. Sellers now are in a tough position where they would ; 

1) obviously move forward with deal and close of escrow as planned sooner.

2) wiling to work with buyers but don't want them to back-out at the end of due diligence period without any compensation for loss of opportunity.

3) Seller are contemplating to ask for a non-refundable deposit from buyers if they choose to cancel the deal and walk away at the end of the (90) days extension.

4) what is fair and reasonable under these circumstances as I don't want to risk the buyer canceling the deal completely, but also don't want the seller end up with absolutely nothing? 

thank you for any feedback. 

Ricardo