John Henry, owner of the Boston Red Sox answers a question during a press conference in London, Tuesday, May 8, 2018, to announce a two game series to be played in London. The Boston Red Sox and the New York Yankees will play a MLB two game series at the London Stadium in London, June 29-30 2019. Credit: Alastair Grant | AP

Billionaire John Henry has shown interest in buying a stake in NASCAR, potentially adding to a sports empire that includes the Boston Red Sox and the Liverpool Football Club, people familiar with the situation said.

NASCAR has been seeking minority investors, and Henry is already involved with the stock-car racing organization. His company, Fenway Sports Group, formed a partnership in 2007 with Roush Racing, home to drivers such as Matt Kenseth and Ricky Stenhouse Jr.

Representatives for NASCAR and Fenway Sports declined to comment. The people familiar with the deliberations asked not to be identified because the matter is private.

NASCAR, meanwhile, is laying the groundwork for a transaction. Last month, it bid roughly $1.9 billion for International Speedway Corp., a deal that would more tightly combine the companies. Both businesses are already controlled by the France family, and merging the assets may make it easier for a new investor to step in.

That deal would create a closely held group with the France family as the primary owners. Jim France currently serves as chairman of ISC and interim chief executive officer of NASCAR.

Shares of Daytona Beach, Florida-based ISC gained almost 2 percent on Tuesday after Bloomberg reported on the possible Henry investment.

NASCAR is seeking investors at a time of falling ratings and the loss of some big sponsors, including Lowe’s Cos. Drivers such as Danica Patrick, Dale Earnhardt Jr. and Jeff Gordon have retired, leaving the sport with fewer superstar draws.

Henry bought the Red Sox in 2002 — just ahead of a run of championships, including one this year. The 69-year-old investor, who also owns the Boston Globe, has a net worth of $2.5 billion, according to Forbes. He made his fortune in commodities trading.