The best place to start with a new material is often the trash can. For Julia Marsh, the Californian designer behind Sway, the starting point was the polybag, the thin, crinkly plastic sleeve that protects a new shirt or a pair of shoes on its journey from factory to closet. Marsh, inspired by a lifelong affection for the ocean, wondered what would happen if you made it from seaweed instead, and designed it to disappear in a backyard compost pile [Prime Brown University] [The Helm].
Sway, founded in 2020 and based in Oakland/Berkeley, is betting that the answer is a viable business. The company has developed a line of home-compostable packaging films derived from seaweed, aiming to match the performance of conventional plastic while slotting into existing manufacturing equipment [F6S] [Designer Fund, 2023].
The Regressive Resource
The core of Sway's pitch is the resource itself. Seaweed grows quickly, requires no freshwater, fertilizer, or arable land, and actively sequesters carbon while improving ocean health [Parley]. Sway's technical challenge has been to turn that seaweed into a thermoplastic resin that behaves like the plastic brands and manufacturers already know. The company says it has developed a patented seaweed-based biopolymer that works as a drop-in solution within traditional plastic infrastructure [The Helm]. Their first commercial product is a home-compostable polybag, printed with ink derived from algae. Sway's February 2024 press release names J.Crew, Burton, and others as brand partners. Crunchbase additionally lists Dr. Bronner's and Faherty as customers [Author note, May 2026].
Validation Before Volume
For a pre-revenue materials startup, credibility is currency. Sway has been aggressive in collecting it through awards and high-profile recognition:
- Prize money. The company was a winner of the Tom Ford Plastic Innovation Prize in 2023, receiving $600,000, which included a direct equity investment from Trousdale Ventures [Packaging World] [Author note, May 2026].
- Industry challenge. It previously won the Beyond the Bag Challenge run by the Closed Loop Partners consortium in 2021 [F6S].
- Media landmark. In late 2024, Sway and founder Julia Marsh were profiled in Oprah Daily [Oprah Daily, Oct 2024].
- Invention list. Most recently, Sway Seaweed Packaging was named one of TIME's Best Inventions of 2025 [Sway TIME, 2025].
This track record has helped attract an estimated $7,500,000 in total funding from a mix of impact and venture investors, including Valor Siren Ventures, Alante Capital, BAM Ventures, The Helm, and Third Nature [Sway Funding] [Author note, May 2026].
Founders, Backgrounds, and Bench
The founding team reflects the product's origin at the intersection of design, brand strategy, and environmental science. CEO Julia Marsh is a designer focused on scaling regenerative technology with consumer brands [PatSnap]. Her life and business partner, Matt Mayes, serves as COO, with a career centered on improving sustainability practices within large organizations [The Org]. Leland Maschmeyer, an early creative contributor, is the Chief Creative & Strategy Officer at Chobani [PatSnap] [TechCrunch, 2020].
| Founder | Role | Background |
|---|---|---|
| Julia Marsh | CEO & Co-Founder | Designer, scaling regenerative tech with brands. |
| Matt Mayes | COO & Co-Founder | Sustainability operations for large organizations. |
The Scaling Equation
The road from a prize-winning prototype to a commodity-scale material is long, expensive, and littered with the skeletons of promising bioplastics. Sway's most immediate challenge is proving it can manufacture consistently, at volume, and at a cost that brands can swallow. The company has not disclosed any production capacity figures or per-unit pricing. Sway's bet is that its focus on thin films for fashion and its drop-in manufacturing compatibility will carve out a specific and valuable niche. For Sway to succeed, it must ultimately beat the incumbent not on feel-good branding, but on cold, hard unit economics.