Sizing bitcoin treasuries with long-duration capital

Start with the risk budget, not the headline number

If you manage long-duration capital — an endowment, a family office, a permanent reserve — the hard question is not whether bitcoin belongs in the portfolio. It is how much you can hold through a severe drawdown without being forced to sell. Position sizing usually matters more than asset selection, because the failure mode is rarely picking the wrong asset; it is holding a position so large that volatility forces a sale at the worst moment.

The practical answer is to size from the risk side. BlackRock's institutional research describes a risk budgeting approach: size the allocation by how much it contributes to total portfolio risk, measured by long-run volatility and correlation to other assets. That framing turns a conviction debate into an arithmetic one.

What the published ranges actually say

Most large institutions that publish a number land in low single digits. BlackRock's Investment Institute called 1–2% a reasonable range for a multi-asset portfolio, on the grounds that its risk contribution there is comparable to a single mega-cap tech holding. Bank of America Private Bank has cited 1–4% for digital assets. Fidelity Digital Assets research found 1–5% allocations improved Sharpe ratios in traditional portfolios.

A useful summary of the institutional consensus is that institutions cluster around a 1–5% BTC allocation. The same source notes that above roughly 10%, the portfolio starts to behave like bitcoin itself, and below about 0.5%, the upside barely moves total returns.

The reason the range is so low is volatility. Bitcoin has historically run 5–10x the volatility of equities. A 5% bitcoin weight at 70% annualized volatility contributes roughly the same portfolio risk as a 30% equity weight at 15% volatility. At a 4% weight, bitcoin already contributes about 7.4% of total portfolio risk — roughly twice its weight.

Translate a risk budget into a weight

CoinShares modeled this directly: a modest 100 basis point increase in portfolio risk budget implies roughly a 3.6% bitcoin weight, and a 120 basis point risk budget implies about 4%. That is the cleanest bridge from "how much risk can I add" to "how many dollars do I allocate."

A workable sequence:

1. Set the risk budget first. Decide how many basis points of total portfolio volatility you are willing to add. Long-duration capital can tolerate more than a near-term liability pool, but the number should be explicit.
2. Convert to a weight. Use long-run volatility and correlation, not a single backtest window. CoinShares notes that varied back-test periods produce consistent results, which reduces the cherry-picking problem.
3. Stress-test the drawdown. Bitcoin has seen peak-to-trough drawdowns of 77%, 84%, and 93% in different cycles. Ask whether the position size survives that without forced selling.
4. Fix a rebalancing rule. CoinShares research found that keeping a fixed allocation and rebalancing quarterly helps mitigate bitcoin's volatility.
5. Separate the funding source from the reserve. If income from other portfolio engines funds the bitcoin position, the reserve can be held as long-duration capital rather than sold opportunistically.

Why long-duration capital changes the math

Institutions built on permanent capital — endowments, insurers, sovereign funds — do not mark to market daily and do not panic at the bottom. That structural patience is exactly what bitcoin exposure requires. As one analysis argues, bitcoin treasuries are not arbitrage — they are the next endowments, because they are built on permanent capital and long-dated obligations.

Adoption data supports the shift from tactical to strategic. Institutional investors held a 22.9% share of total US bitcoin ETF AUM at the end of Q1 2025, and within that, advisor holdings rose in BTC terms while hedge fund exposure fell by nearly a third — a rotation from short-term tactical positioning toward longer-term ownership, according to CoinShares' 13F analysis.

For a long-duration allocator, the implication is straightforward: the right size is the largest position you can hold through a 90% drawdown without changing your behavior. For most institutional portfolios, that lands in the low single digits.

Quick checklist

• Write down your risk budget in basis points before choosing a weight.
• Use long-run volatility and correlation, not a favorable backtest window.
• Confirm the position survives a 77–93% drawdown without forced selling.
• Set a fixed allocation with a quarterly rebalance rule.
• Define the funding source separately from the reserve.
• Document the liquidity and custody structure before funding.

Test your understanding

Before you finalize a sizing framework, check whether you have internalized the core arithmetic that drives institutional allocation ranges.

How the Featured Expert Can Help

Mehle Capital is an institutional equity fund that pairs concentrated public equity holdings with a Bitcoin commodity treasury, targeting qualified investors with a minimum commitment of $100,000. The firm, led by founder and CIO Chad Mehle, emphasizes long-duration capital, inflation-resistant architecture, and a disciplined investment approach rooted in two decades of institutional experience. You can learn more at Mehle Capital.