Notorious real estate flip-addict Michael Holtz, who is also the founder and CEO of travel business company SmartFlyer, has listed his four units at 165 Charles St. for $14 million.

If combined, the units would become a four-bedroom, six-bathroom full-floor home — or the buyer could leave one unit separate as a staff or in-law guest apartment, notes the listing from brokers Jon Capobianco and Scott Hill, of Compass.