Shares of Carvana dropped about 6.3% Tuesday as worries swirl that a federal investigation into one of its investors, Mark Walter, could lead to the billionaire selling his stake of the used car retailer. After falling yesterday, Carvana shares are now down about 13% this week. One market strategist told Bloomberg that the expectation that Walter might sell his stake is contributing to weakness in Carvana shares.

Read more on the probe and Walter's business and sports empire here.