Ferdinando Holthaus and Jody Debest Holthaus sold a condo at 259 21st St. Unit #3J in Sunset Park West to Matt Kronsberg and Sigrid Jacob for $900,000 on Oct. 4.

Mr. and Ms. Holthaus paid $610,000 for the property in Jan. 2005. The unit is part of the four-story St. John condo development.

Mr. Holthaus is a senior executive at Mackenzie Keck, a construction firm founded in 1992. Prior to joining Mackenzie, he was project manager store planning for North and South America at Geox Inc. and senior project manager at Michili Inc.

He attended Academia di Belle Arti Firenze in Florence, Italy.

According to BlockShopper.com, there have been 15 condo sales in Sunset Park West during the past 12 months, with a median sales price of $365,000.