Sources indicate that Peter Thiel's Founders Fund is finalizing its fourth growth fund, Founders Fund Growth IV, with capital commitments approaching $6 billion. This raise represents a significant expansion for the San Francisco-based firm, with demand from outside investors surpassing the fund's capacity. Approximately $1.5 billion of the total capital is being contributed by the firm's own partners. This new vehicle comes less than a year after the firm closed its third growth fund, which totaled $4.6 billion and was designed primarily for follow-on investments in existing late-stage companies. The move underscores Founders Fund's aggressive strategy to support mature portfolio companies through their growth phases rather than focusing solely on early-stage startups, a segment for which the firm has not raised a dedicated fund since early 2022. The 21-year-old firm boasts a history of backing high-profile successes. Its portfolio includes early investments in AI cloud computing firm Crusoe, fintech giants Stripe and Ramp, and workforce management platform Rippling. Notably, Founders Fund was the first institutional investor in Palantir Technologies and has maintained stakes in several defense technology companies, including SpaceX, Flock Safety, and Anduril. Anduril, co-founded by partner Trae Stephens, is reportedly in the process of raising a massive $4 billion round at a $60 billion valuation. Beyond its existing ecosystem, Founders Fund is actively expanding its footprint in the artificial intelligence sector. Last month, the firm made its first direct investment in Anthropic, co-leading a massive $30 billion funding round that valued the AI company at $380 billion on a post-money basis. This strategic move, alongside its investment in OpenAI, positions Founders Fund as one of the few venture capital firms holding significant stakes in both leading AI laboratories. In contrast to its recent growth-focused activity, the firm scaled back its early-stage operations in response to challenging market conditions in 2023. The originally announced $1.8 billion early-stage fund was cut in half, with the remaining $900 million reallocated to a new early-stage vehicle that officially launched last October. While Founders Fund continues to demonstrate strong capital formation capabilities in the growth stage, the firm declined to comment formally on the $6 billion fundraising milestone. The completion of this fund reinforces the firm's position as a dominant player in the venture capital landscape, particularly within the AI and defense technology sectors.