Overall, about 4,800 owners have at least started the application process to seek an exemption, the Finance Department spokesperson said. The levy targets single-family homes worth $5 million or more and apartments worth $1 million or more. City officials extended by four weeks the deadline for property owners to file for exemptions. Owners now have until September 18 to submit applications, a response to concerns about the compressed timeframe for property owners to gather and submit the necessary documents. In July, the Finance Department published a spreadsheet of nearly 1 million residential properties that it said may be subject to the new tax.