The sale is dead. Motasem Khashoggi — a cousin of the late Saudi arms dealer Adnan Khashoggi — failed to deliver a $100 million deposit by the Oct. 13 deadline. The deposit never came; the bill never left.

Residents of the East 61st Street co-op — some of whom are among the wealthiest people in America — last week escaped a highly contested $2 billion buyout that would have forced them from their homes. The co-op must now work out a renovation and funding plan with Taj Hotels, the building’s current operator.

I read this as a classic co-op capital call with no underwriting: the board has a number, the operator has a different number, and the residents have no number at all.

A Pierre shareholder familiar with the discussions said the board has commissioned a new engineering report to determine the price of repairs. Taj previously reported repairs to the tune of $300 million. A person familiar with the building on Tuesday told The Post repair costs edged closer to $400 million. The final division of costs, and whether shareholders will face stratospheric monthly bills, remain unresolved as negotiations continue.

Engineering studies identified water intrusion and corroded pipes. According to Vanity Fair, the facade is already undergoing a $22 million overhaul. Another shareholder told The Post residents could remain during these renovations and expressed optimism about restoring the property without displacement. For longtime residents, the Pierre represents a home and community, the source said, describing elderly neighbors who have lived there for decades and employees regarded as family.

Ask your board: what’s our number, and who’s writing the check when the next engineering report lands?