Bolt Threads manufactures vegan “spider” silk and mycelium-based materials. Bolt Threads develops isolated silk proteins from proteins inspired by spider silk through a yeast fermentation process. The company’s Microsilk products are sold under its clothing brand, Best Made Co. The company has also developed another biomaterial using mushroom-based mycelium, an alternative leather product branded as Mylo, which is produced on a larger scale. 

In September 2021, Bolt Threads announced its plans to produce Mylo on a commercial scale by the end of 2022 and expected to collaborate with mushroom farmers to heighten its mycelium crops.For its Microsilk product, Bolt had a production capacity of 32,000 sq ft per annum as of 2018. Since Microsilk remains significantly more expensive than traditional silk, the founders were seeking ways to scale up. 

Key customers and partnerships

For its Microsilk product, Bolt Threads launched its first collaboration in 2017 with fashion designer Stella McCartney and introduced its second prototype in the form of a biodegradable tennis dress.  

The leather alternative Mylo has been used in collaborations with Stella McCartney, Seattle-based leather bag manufacturer Chester Wallace, and Canadian athletic apparel retailer Lululemon. In October 2020, The Mylo Consortium was also formed including Adidas, Stella McCartney, Kering, and Lululemon, who collectively have made a seven-figure investment into Bolt Threads to produce Mylo. In return for their investments, these brands would have access to a large supply of the product. 

Stella McCartney has been experimenting with Mylo to create clothing prototypes with plans to use the material in upcoming collections. Adidas used Mylo to produce high-performance footwear for the first time in April 2021 by making a vegan version of its “Stan Smith” sneaker design that dates back to 1965 and had plans to expand the use of Mylo material in its other products including handbags, wallets, shoes, jackets. In February 2022, Lululemon launched a Mylo-based yoga bag collection, which included a multipurpose yoga bag and a storage bag for workout gear. Mylo was also used by Danish luxury brand Ganni for the launch of its limited edition Mylo-based wallet range and one-of-a-kind saddle-bags in June 2022. Ganni’s partnership with Bolt Threads included plans to release more Mylo-based products in Q1 2023. With growing demand for its Mylo product, in February 2022, the company partnered with Mycelium Materials Europe (MME) for the commercial production of Mylo. 

Funding and financials

The company’s last funding round was a USD 123 million Series D in January 2018 led by Baillie Gifford. The funds were used to commercialize the company’s Microsilk products.