Form Q-10s are quarterly reports of a company's performance that all publicly traded companies are required to submit to the SEC.
The NHTSA is investigating the May 7 crash involving Brown, as well as a July 1 non-fatal crash in Pennsylvania involving a Tesla Model X, to see whether autopilot was functioning at the time of the second accident, Reuters reported on Tuesday.
Autopilot is a "semi-autonomous technology that helps drivers steer and stay in lanes," according to Reuters, which added that the autopilot function was still in test mode.
Tesla has said that drivers should keep their hands on the wheel, even while the car was partially controlling its own movements.
In the Wednesday blog post, Tesla wrote that the damage sustained by Brown's Model S made it difficult for the company to recover data from the care remotely. It was not until May 18 that a Tesla investigator was able to go to Florida to inspect the car and crash site, and Tesla did not complete its own investigation into the accident until the last week of May, the company said.
"To be clear, this accident was the result of a semi-tractor trailer crossing both lanes of a divided highway in front of an oncoming car. Whether driven under manual or assisted mode, this presented a challenging and unexpected emergency braking scenario for the driver to respond to," Tesla wrote.
"In the moments leading up to the collision, there is no evidence to suggest that Autopilot was not operating as designed and as described to users: specifically, as a driver assistance system that maintains a vehicle's position in lane and adjusts the vehicle's speed to match surrounding traffic."
In an apparent reference to Fortune's second story, Tesla accused the magazine of "plucking boilerplate language from SEC filings that have no bearing on what happened."
It also said that the fact Tesla stock ended July 1 up, not down, confirmed that investors understood that the information was not material. Tesla has not received a product liability claim in relation to the Florida crash, the company said.
Tesla's stock closed 0.2 percent higher on Wednesday at $214.44 per share.
An editor at Fortune magazine told CNBC that "in reporting both articles, Fortune reached out to both Tesla and Musk for comments, in particular seeking to find out when exactly they knew about the accident, and why it wasn't disclosed."
"After the articles were published, Tesla wrote Fortune a rebuttal, which we published in full on our website, here. Fortune fully stands by its reporting and both articles, and continues to believe that the fact that an accident had occurred and that the company and regulators were investigating was a material fact that Tesla had an obligation to disclose to potential shareholders."
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