Key Takeaways
- • Bloomberg Intelligence analysts Eric Balchunas and James Seyffart published "Both Sides of the Coin" through Harriman House, a bitcoin book drawn from roughly 18 months of research and framed as an analyst's guide to how the asset reached brokerage accounts.
- • Spot bitcoin ETFs grew to $150 billion in assets in their first 18 months and absorbed about 1.4 million bitcoin, roughly 7% of total supply, according to the book.
- • U.S. bitcoin ETF assets fell from $169 billion in October 2025 to $109 billion in May, with about 90% of the decline attributed to falling prices rather than redemptions, per Balchunas; cumulative net inflows dipped from a peak near $62 billion to about $53 billion before recovering to about $59 billion.
- • The book scores bitcoin against gold as roughly even in a "Store of Value Smackdown," though U.S. gold ETFs held about $178 billion more in assets than bitcoin ETFs based on May data.
- • The authors offer no investment advice, citing Bloomberg restrictions, and acknowledge the book leans positive while presenting risks, including quantum computing and AI threats to security.
Summary
Bloomberg Intelligence senior ETF analyst Eric Balchunas and colleague James Seyffart have published "Both Sides of the Coin," a bitcoin book released by Harriman House. According to the book's opening note, Balchunas spent 18 months studying the asset before writing it with Seyffart. The authors describe Balchunas as the "tourist" and Seyffart as the "native," and the book is framed less as a crypto manifesto than as an analyst's account of how bitcoin reached brokerage accounts. Neither author offers investment advice, citing restrictions tied to their roles at Bloomberg, and the authors acknowledge that the book leans positive while stating they aimed to "present the risks and let the reader be the jury."
The book's central backdrop is the rapid growth of spot bitcoin ETFs. According to the book, these products reached $150 billion in assets within their first 18 months and absorbed about 1.4 million bitcoin, roughly 7% of total supply. A key chapter traces BlackRock's path to its iShares Bitcoin Trust ETF (IBIT), including a private bitcoin trust code-named "Trust 91" that drew little early interest until a $10 million investment from Anthony Scaramucci's SkyBridge Capital became the first outside money in a BlackRock bitcoin product. The authors write that the ETF "likely would never have got off the ground" without that backing, and that a January 2023 pitch to BlackRock's management committee won support "although barely." They also argue Larry Fink's shift from calling bitcoin an "index of money laundering" was likely driven as much by revenue potential as by commitment to the asset.
On risk, Balchunas identified security as bitcoin's weakest point, comparing the asset to "a tank" that trades speed for safety, with quantum computing or AI representing the largest threat, though he assigns low odds to it. He also noted that bitcoin generates no cash flows, calling it "really just based on sentiment and more of a psychological asset." On fund selection, Balchunas said investors can rely on the eight or nine original spot funds, which charge between 15 and 25 basis points, and that long-term holders should prioritize the lowest expense ratio while shorter-term investors should focus on liquidity. He questioned the rationale for bitcoin futures ETFs, which predate spot funds and cost more to run.
The book's comparison with gold, titled "Store of Value Smackdown," finds gold ahead on track record, volatility and diversification, while bitcoin leads on portability, storage and taxes. Per the book's May data, U.S. gold ETFs held about $178 billion more in assets than bitcoin ETFs. The authors also recount Jack Bogle's warning that investors should avoid bitcoin "like the plague" and note that Vanguard barred spot bitcoin ETFs from its brokerage for almost two years before reversing in December 2025.
The book arrives after a difficult period for bitcoin ETFs. Per the book's data, U.S. bitcoin ETF assets fell from $169 billion in October 2025 to $109 billion in May, with Balchunas attributing about 90% of the decline to falling prices. Cumulative net inflows peaked near $62 billion, dipped to about $53 billion and have since recovered to roughly $59 billion.
The book's central backdrop is the rapid growth of spot bitcoin ETFs. According to the book, these products reached $150 billion in assets within their first 18 months and absorbed about 1.4 million bitcoin, roughly 7% of total supply. A key chapter traces BlackRock's path to its iShares Bitcoin Trust ETF (IBIT), including a private bitcoin trust code-named "Trust 91" that drew little early interest until a $10 million investment from Anthony Scaramucci's SkyBridge Capital became the first outside money in a BlackRock bitcoin product. The authors write that the ETF "likely would never have got off the ground" without that backing, and that a January 2023 pitch to BlackRock's management committee won support "although barely." They also argue Larry Fink's shift from calling bitcoin an "index of money laundering" was likely driven as much by revenue potential as by commitment to the asset.
On risk, Balchunas identified security as bitcoin's weakest point, comparing the asset to "a tank" that trades speed for safety, with quantum computing or AI representing the largest threat, though he assigns low odds to it. He also noted that bitcoin generates no cash flows, calling it "really just based on sentiment and more of a psychological asset." On fund selection, Balchunas said investors can rely on the eight or nine original spot funds, which charge between 15 and 25 basis points, and that long-term holders should prioritize the lowest expense ratio while shorter-term investors should focus on liquidity. He questioned the rationale for bitcoin futures ETFs, which predate spot funds and cost more to run.
The book's comparison with gold, titled "Store of Value Smackdown," finds gold ahead on track record, volatility and diversification, while bitcoin leads on portability, storage and taxes. Per the book's May data, U.S. gold ETFs held about $178 billion more in assets than bitcoin ETFs. The authors also recount Jack Bogle's warning that investors should avoid bitcoin "like the plague" and note that Vanguard barred spot bitcoin ETFs from its brokerage for almost two years before reversing in December 2025.
The book arrives after a difficult period for bitcoin ETFs. Per the book's data, U.S. bitcoin ETF assets fell from $169 billion in October 2025 to $109 billion in May, with Balchunas attributing about 90% of the decline to falling prices. Cumulative net inflows peaked near $62 billion, dipped to about $53 billion and have since recovered to roughly $59 billion.
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