Neuralink has added $43 million to a previously announced venture funding tranche, according to a filing with the SEC. The increase brings the tranche, led by Founders Fund, from $280 million to $323 million.
What the filing says about Neuralink’s funding
The filing, published this week, says 32 investors participated. It records the larger total in early August, but does not disclose a recent company valuation.
Reuters reported in June that Neuralink was valued at about $5 billion after privately executed stock trades. That figure reflects reported private transactions; the funding filing itself focuses on the amount raised and the investors involved.
For Neuralink, the additional capital arrives as it develops an implantable system intended to read brain signals. The filing offers a snapshot of investor participation, but does not explain how the company plans to use the added funds.
How the brain implant is designed
Founded in 2016, Neuralink has developed a device described as similar to a sewing machine. It is designed to place ultra-thin threads inside the brain, where they connect to a custom chip containing electrodes.
The electrodes can read information from groups of neurons. Brain-signal-reading implants have existed for decades, while Neuralink’s stated technical distinction is to make implants wireless and increase the number of electrodes implanted.
In practical terms, the system combines threads placed in the brain with electronics that collect neural information. The source does not provide details on the implant’s performance or how much information it can read, so the funding news does not establish what the technology can accomplish in use.
Human trials bring a new phase
In May, Neuralink received FDA approval for human clinical trials after its application had previously been rejected. The company then opened recruitment for its first human trials under an investigational device exemption by the FDA.
Approval to begin clinical trials marks a step toward testing the implant in people. Recruitment is the beginning of that process, rather than evidence in itself about the device’s safety or effectiveness.
The transition to human research also puts greater focus on how the system is developed and evaluated. The source describes the trial authorization alongside a history of criticism and investigations, making oversight an important part of the story.
Criticism and investigations remain part of the story
Neuralink has faced allegations of a toxic workplace culture and unethical research practices. In a January 2022 article in Fortune, anonymous former employees described a “culture of blame and fear.” They said Musk would encourage junior employees to send issues and complaints to him directly, a practice they said undermined management.
By August 2020, three of the company’s eight founding scientists remained. Stat News described the departures as part of internal conflict where rushed timelines clashed with the slower, incremental pace of science.
Animal research has also drawn scrutiny. In 2022, the Physicians Committee for Responsible Medicine (PCRM) alleged that Neuralink and UC Davis, its former research partner, mistreated several monkeys used to test the hardware. The group alleged psychological distress and chronic infections related to surgeries.
Reports from Reuters and Wired suggested that testing was rushed in response to Musk’s demands for fast results, and described complications with electrode installation, including partial paralysis and brain swelling. The U.S. Department of Agriculture (USDA) investigated Neuralink for nearly a year over animal welfare violations. It concluded there was “no evidence” of breaches in the trials beyond a previously self-reported incident from 2019; PCRM disputed the investigation’s results.
In November 2023, U.S. lawmakers asked the SEC to investigate whether Neuralink omitted details about the deaths of at least a dozen animals surgically fitted with its implants. These claims, the USDA’s conclusion and PCRM’s disagreement are distinct parts of the record described in the source. Together, they show why the company’s funding and clinical ambitions are being followed alongside questions about research practices and oversight.