Delek sold the 2.5% stake at $27.78 a share after the market closed on Thursday. Delek US shares fell 6.4% on Friday to $26.76.
As a result of the sale, Delek will cease to consolidate Delek US results in its financial statements as of the second quarter.
Delek will post an after-tax gain of NIS 450 million ($126 million) to NIS 500 million in the second quarter for the sale as well as for a revaluation of its remaining stake in Delek US.
Delek Group is a partner with Texas-based Noble Energy in Israel's largest natural gas discoveries.