Stillmark is a Bitcoin-focused venture capital firm based in the United States. Founded in 2019 by Alyse Killeen, the firm takes a thesis-driven approach: it invests exclusively in companies building on or around Bitcoin, deliberately excluding the broader altcoin and general crypto ecosystem. This narrow focus sets Stillmark apart from most crypto funds, which typically spread capital across multiple blockchains and tokens.
Killeen built her investment career in early-stage technology before pivoting to Bitcoin-native companies. At Stillmark she serves as founder and managing partner, and has spoken publicly about Bitcoin's unique properties – fixed supply, decentralization, and security – as the reason to concentrate the fund's thesis there. The firm targets seed and early-stage rounds, writing initial checks into infrastructure, financial services, and consumer applications that derive their core value from the Bitcoin network. Public information about the fund's total AUM is limited; no official figure has been disclosed as of mid-2025.
Notable investments
- Lolli – a Bitcoin rewards platform that lets users earn BTC when shopping at major retailers. One of Stillmark's most visible early bets on Bitcoin consumer adoption.
- Fold – a Bitcoin rewards debit card and app, giving users BTC back on everyday purchases.
- Unchained Capital – a Bitcoin financial services company offering collaborative custody, loans, and inheritance planning secured by Bitcoin multisig.
- Swan Bitcoin – an automated Bitcoin savings platform aimed at long-term retail accumulation.
- Titan – a Bitcoin mining infrastructure company.
Public information on the full portfolio breadth beyond these names is limited. Stillmark lists 11 portfolio companies total per available metadata, with 3 marked as lead investments.
Team
Alyse Killeen is the primary public face of Stillmark. She has appeared at Bitcoin conferences including Bitcoin Conference and has written and spoken on the investment case for Bitcoin-only company building. Detailed information about additional partners or analysts on the team is not widely disclosed in public sources.
Recent activity
Through 2024 and into 2025, Stillmark maintained its Bitcoin-only discipline during a period when many generalist crypto funds rotated capital toward Ethereum layer-2 networks, Solana, and AI-adjacent blockchain projects. Killeen has been publicly consistent: the fund does not intend to broaden its scope. Several portfolio companies – including Fold and Unchained – raised follow-on rounds during this period from other investors, suggesting early Stillmark bets held their value as the Bitcoin price recovered toward and beyond all-time highs in late 2024.
No material fund closings, exits, or failures have been confirmed publicly as of the available information. The firm has not disclosed write-downs or notable portfolio losses, though the Bitcoin-only mandate means exposure to regulatory and liquidity risk is concentrated in a single asset class.
Stillmark occupies a specific niche: a small, conviction-driven fund betting that Bitcoin's dominance as a monetary network will produce the most durable equity returns in the sector. Whether that thesis pays out at fund scale remains to be seen, but the portfolio companies selected – payments, custody, savings, mining – reflect a coherent view of where Bitcoin-native value accrues. Investors and founders seeking a partner with deep Bitcoin-specific expertise and a long time horizon will find Stillmark one of the few funds that fits that profile. Further verified data is available via Crunchbase.