Advisors now field two questions about bitcoin allocation, not one: how much a client should hold, and alongside what. Both need a structured answer rather than a general view on the asset class. 21shares research tested one across the three years to September 30, 2026.

[Download: From theory to allocation: Managing Bitcoin and digital assets in client portfolios]

Bitcoin’s correlations stayed well below those between traditional assets

Bitcoin’s three-year correlation was 38% with US equities, 11% with real estate and 4% with gold, using one-month rolling returns from October 2023 to September 2026 (21shares, TradingView). US equities and emerging market equities correlated at 65% over the same period.

The relationship moves. Bitcoin’s short-term correlation with gold rose to around 50% by the end of September 2026, from 44% in June, while its equity correlation eased below 40%. When a client asks why bitcoin tracked gold in one quarter and not another, 21shares research views the diversification benefit as structural over a full cycle rather than present in every quarter.

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Bitcoin’s volatility has moved into the range of high-growth equities

Bitcoin’s rolling three-month volatility averaged close to 60% before 2024 and about 38% since US spot bitcoin exchange-traded products (ETPs) launched in January 2024 (21shares, TradingView, July 2013 to September 2026). Over the 12 months to September 30, 2026, measured on US trading days, its annualized volatility was 44%, against 46% for Tesla and 59% for Palantir (21shares, TradingView).

That comparison matters for clients who already hold high-growth equities. It does not make bitcoin low-risk: the 60/40 benchmark in the backtest below ran at 11.25%, and Ethereum and Solana ran at about 46% and 50% on the three-month measure.

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Bitcoin, Ethereum and Solana play different roles in a portfolio

21shares research places bitcoin in the alternatives sleeve alongside gold, and Ethereum and Solana in the technology equities sleeve. Bitcoin has a supply fixed at 21 million by its protocol, which some market participants view as protection against currency debasement; the thesis is contested.

Ethereum does something structurally different: it is a network on which payment, lending and trading applications run, with value that rests on adoption and usage fees. Solana is a younger network built for faster, cheaper transactions and is treated as a higher-risk growth satellite. Their three-year correlations to technology equities were 45% and 32% (21shares, TradingView, October 2023 to September 2026).

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A 2% to 5% allocation improved risk-adjusted returns in the backtest

Over October 2023 to September 2026, three hypothetical digital asset profiles funded from the equity sleeve each improved the Sharpe ratio of a 60/40 portfolio with quarterly rebalancing (21shares, TradingView). The Sharpe ratio measures return earned per unit of volatility.

Volatility rose by 0.02 to 0.43 percentage points and maximum drawdown deepened by 0.12 to 1.34 percentage points. The window was one of steady gains for digital assets. Backtested results are hypothetical, do not represent actual outcomes, and past performance is not a reliable indicator of future results. Allocations should reflect each client’s suitability assessment.

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Rebalancing keeps the allocation at the size the client chose

Without rebalancing, the growth profile’s maximum drawdown reached 17.83% against 14.82% with quarterly rebalancing, and its volatility rose from 11.68% to 13.48% (21shares, TradingView, October 2023 to September 2026). From September 2020 to September 2023, which included the 2021 rally and the 2022 drawdown, quarterly rebalancing held the same profile’s maximum drawdown to 31.37%, against 28.69% for the benchmark and 50.56% without it.

Rebalancing did not lift returns in every test, and the research finds that a consistent rule matters more than the exact frequency. Agreeing the rule when the client agrees the size fixes the intended exposure in advance. Download the full report, From theory to allocation: managing digital assets in client portfolios, for the method and results across all five rebalancing frequencies.

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FAQ

How much bitcoin should be in a client portfolio? There is no single figure: sizing depends on each client’s risk profile and suitability assessment. In a hypothetical 21shares backtest of a 60/40 portfolio over October 2023 to September 2026, allocations of 2% (bitcoin), 4% (bitcoin and Ethereum) and 5% (bitcoin, Ethereum and Solana) each improved the Sharpe ratio. Past performance is not a reliable indicator of future results.

Is bitcoin correlated with the stock market? Bitcoin’s correlation with US equities was 38% from October 2023 to September 2026, using one-month rolling returns, against 65% between US and emerging market equities (21shares, TradingView). The figure changes by period and can rise during short bouts of market stress.

Is bitcoin more volatile than stocks like Tesla? Over the 12 months to September 30, 2026, bitcoin’s annualized volatility was 44%, against 46% for Tesla and 59% for Palantir, measured on US trading days (21shares, TradingView). All three sit well above the 11.25% annualized volatility of the 60/40 portfolio in the same 21shares backtest.

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