Most multimillion-dollar mansions are so unique that it's pretty much impossible to have a formulaic pricing strategy when listing them.
According to Candace Jackson of The Wall Street Journal:
Pricing homes at the extreme high end of the market is a somewhat subjective, and often irrational, process. Because there are so few similar properties for sale, and the homes are often unique, it's difficult to set a standard for a pricing scale, brokers say. For a home priced above $30 million, a "reasonable" price may be in the eye of the beholder."
Most of these homes are custom-made, have had millions of dollars of renovations put into them, and can have over-the-top amenities. They are hard to appraise since they are so unique and rare, making pricing essentially a crapshoot after the value of the land is accessed.
The hard-to-value mansions have led to an interesting trend: some homes that aren't selling actually get a price increase rather than a deduction.
Jackson notes that according to Zillow, 436 New York area listings over $1 million had raised their prices in the past 12 months, compared with 266 for the same period two years earlier.
Raising the price creates a mystery factor among potential buyers, who inquire to find out what changed about the listing to warrant the higher price.
"In the end, sanity usually wins the day and the price comes back down to reality," Donna Olshan, a New York-based broker told The WSJ. "You can't trick the market."