A regulatory filing says officials have asked about software that Elon Musk, the chief executive, has said would allow cars to operate autonomously.
The automaker reduced the price of the Mustang Mach-E by up to $5,900 after Tesla slashed prices of its cars by as much as 20 percent.
Shares in the electric carmaker continued to rally after the company reported strong profits, even amid growing competition and economic pressures.
The electric car company is facing intensifying competition, supply chain disruptions and concerns about the behavior of Elon Musk.
The $3.6 billion investment, which also includes a new battery factory, presents a challenge to traditional truck makers that have been slow to sell electric vehicles.
Under questioning, Mr. Musk said he hadn’t discussed how much money investors would put in to help him take his car company private.
Mr. Musk is testifying in a lawsuit filed by investors who claim that his statements about a plan to take Tesla private in 2018 caused them to lose billions of dollars.
The chief executive of Tesla testified in a federal civil trial about a 2018 plan to take the automaker private that fizzled out.
A wave of lawsuits argue that Tesla’s self-driving software is dangerously overhyped. What can its blind spots teach us about the company’s erratic C.E.O.?
Investors are seeking billions of dollars in damages for their losses after Mr. Musk posted a proposal on Twitter that never materialized.