Highstock raises $30M to take its surplus marketplace into apparel

Why it matters

Van Horne is applying Instacart's marketplace playbook to inventory brands usually hide or destroy. The $30 million round funds a larger apparel test, while Highstock still must prove how much of its claimed $1 billion in listings actually sells.

Camille van Horne (@camillevanhorne) is the co-founder and CEO of Highstock, a marketplace for excess consumer inventory. Andreessen Horowitz announced on September 10th, 2026, that it was leading Highstock's $30 million Series A. Highstock is using the capital to move from surplus beauty products into apparel.

The round brings a16z partner Olivia Moore onto Highstock's board and Jeff Jordan in as an adviser, according to a16z's investment announcement. The Series A also includes Greylock, Abstract Ventures, Daybreak Fund and angel investors. Highstock has now disclosed at least $35.5 million in financing, including a $5.5 million seed led by Greylock in February 2025. Highstock did not disclose a valuation.

Van Horne is building software for a part of retail that brands generally prefer customers never see. Highstock connects brands holding unsold products with approved wholesale buyers, while managing bids, logistics, payments, compliance and order paperwork. The pitch is discretion: a brand can clear a warehouse without advertising a fire sale in its main market.

From Instacart fulfillment to liquidation

Van Horne encountered the problem while running fulfillment products at Instacart, where she spent six years and worked through the sudden demand surge of the COVID pandemic. She has described visiting a snack manufacturer's warehouse near the end of her tenure and seeing a large quantity of sellable food headed for destruction.

The University of Chicago graduate earned an MBA from Stanford Graduate School of Business. She co-founded Highstock in 2024 with Ashish Sinha, another Instacart veteran whose family spent approximately 30 years in India's shoe trade. In Highstock's seed announcement, Sinha said his family's experience during pandemic lockdowns showed how much power opaque wholesale relationships could give buyers when a seller needed to move inventory quickly.

That combination shaped Highstock's initial product. Brands list unwanted inventory, vetted buyers submit bids, and sellers accept, reject or counter. Highstock then handles the operational work required to complete the order. Beauty and personal care offered a useful starting point because shelf life creates a deadline.

Van Horne added Sean Cashin as CTO earlier in 2026 after working with him at Instacart. Cashin previously worked as an engineer at Instacart. In her announcement of Cashin's appointment, van Horne described liquidation as a familiar engineering problem involving incomplete product data, shortages and decentralized logistics.

That is the credible version of Highstock's AI argument. Individual lots arrive with inconsistent spreadsheets, different SKUs, geographic restrictions and few clean pricing comparisons. Software can normalize that information, research potential buyers and automate documents. The harder work remains marketplace work: finding enough trustworthy buyers, completing transactions and persuading brands that inventory will not reappear somewhere damaging.

Highstock's $1 billion needs a denominator

Highstock says more than $1 billion of inventory has been listed across over 100 brands, up from the $100 million and 50 brands Highstock reported around its February 2025 seed. According to a16z, more than 100 business buyers use the marketplace. Highstock also reports that it has kept more than 10 million pounds of product out of landfills.

Those figures measure the supply Highstock has attracted and the waste Highstock says it has prevented. They leave the central marketplace economics obscured. Highstock has not published gross merchandise value, sell-through, recovery rates, revenue or take rate. Listed inventory can sit unsold, and the value assigned by a brand does not establish what a wholesale buyer will pay.

The transaction mix provides a stronger indication that Highstock has moved beyond small direct-to-consumer brands. According to a16z, about 60% of transaction volume comes from brands and conglomerates with annual revenue above $500 million. Buyers include overseas retailers and sellers operating live-commerce channels. Highstock has not disclosed the identities of its brands or business buyers.

The Series A gives van Horne room to prove that this supply converts into repeatable transactions. It also gives a16z an ownership position in the operational layer between brands and the increasingly fragmented set of channels willing to sell discounted products.

Apparel tests the marketplace, and the moat

Highstock is now launching in apparel, a category that adds seasonal collections, sizes, colors and faster shifts in demand. Those variables produce more inventory combinations and more potential buyers, exactly the conditions Highstock says its matching software can handle.

Apparel also brings established competition. B-Stock runs liquidation auctions and buy-now listings for returned and overstock inventory. Ghost, a members-only B2B surplus marketplace, offers another private channel. Brokers, jobbers and off-price retailers still have buyer relationships built over decades.

The "AI-native" description offers little protection by itself when rivals make similar claims. Highstock's advantage will come from proprietary transaction data, buyer liquidity and the operational reliability that van Horne and Cashin learned at Instacart. Each completed lot can improve Highstock's understanding of what a buyer wants, what inventory will clear and which restrictions can be honored. Each failed match leaves a brand paying warehouse bills.

That makes the apparel launch the consequential part of the round. Beauty gave van Horne a constrained category with an obvious disposal deadline. Apparel will show whether Highstock can turn her fulfillment experience into a broader wholesale network, rather than a well-stocked catalog of products brands still need to sell.