Tech investor Arthur Becker’s stake in the Cary Tamarkin-designed 10 Sullivan St. — which was around $20 million — keeps paying off.

In 2016, Becker had that stake transferred to three adjacent townhouses — Nos. 30, 40 and 50 Sullivan St. Now he’s listing No. 50 for $12.5 million.

He also just sold No. 30 for $12.29 million.

Prime Manhattan Residential’s Robert Dankner repped the buyer and Becker. Dankner is also 50 Sullivan’s listing broker.

That 25-foot-wide townhouse is more than 5,900 square feet.

Its 1,525 square feet of outdoor space includes an outdoor kitchen, a wet bar and a fireplace.