 Tesla Inc. TSLA, 6.37 stock added to a rally Monday as Chief Executive Elon Musk took the witness stand in a federal trial in San Francisco revolving around his funding secured tweets in 2018. The stock gained more than 6 in midday trading as Musk in court says that he believed he had an agreement with Saudi Arabias investment fund that would be more than sufficient to take the EV maker private. 