Tesla chief executive officer Elon Musk said he had taken four Covid-19 tests and two had come back positive.
The founder of the world's No. 1 electric-car maker also said on Twitter he was experiencing symptoms of a "typical cold. Nothing unusual so far".
The billionaire, who often takes to social media, also mused that other people may be experiencing similar issues with unreliable coronavirus tests.
Tests for the sometimes deadly virus that has infected nearly 53 million people worldwide aren't foolproof and often asymptomatic patients can be found to in fact have the disease.
Mr Musk was in Europe earlier this year to oversee the construction of a factory in Berlin. Tesla also makes electric cars from a plant in Shanghai and one in California.
Something extremely bogus is going on. Was tested for covid four times today. Two tests came back negative, two came back positive. Same machine, same test, same nurse. Rapid antigen test from BD.
— Elon Musk (@elonmusk) November 13, 2020