Businessman Mark Lynch has endorsed Representative Ralph Norman in the Republican primary runoff for South Carolina's U.S. Senate seat.

Lynch, who finished fifth in the August 11 special primary with 5.8 percent of the vote, made the announcement earlier this week. He backed Norman over Senator Darline Graham, who led the primary with 32.8 percent.

Norman received 23.5 percent in the primary and advanced to the August 25 runoff. The special election fills the vacancy created by the death of longtime Senator Lindsey Graham. His sister, Darline Graham, was appointed to the seat and is now seeking the Republican nomination.

In comments to reporters, Lynch described Norman as the true conservative needed to address issues in Washington. He noted that he would support the eventual nominee in the general election against the Democratic candidate.

The runoff is scheduled for August 25. Norman currently represents South Carolina's Fifth Congressional District.