The Israeli-based holding company that owns the majority of Delek US Holdings' shares has sold a 3.7 percent stake in the Brentwood-based company for $57 million. The sale is the third such transaction in four months for Delek Group, which now controls about 53 percent of Delek US. If that number dips below 50 percent, the local company will have to change the way its board of directors operates because it will no longer be considered a "controlled company" under New York Stock Exchange rules.