Bitcoin " HODL" vs Claude Shannon's Demon 50% Bitcoin 50% cash

Claude Shannon described a way to make money off a volatile random walk even if the underlying asset is slowly losing value on average. He asked an audience to consider a stock whose price jitters up and down violently. Put half your capital into the stock and half into a “cash” account. Each day, the price of the stock changes. At noon each day, you “rebalance” the portfolio. That means you figure out what the whole portfolio (stock plus cash account) is presently worth, then shift assets from stock to cash account or vice versa in order to recover the original 50–50 proportions of stock and cash. To make this clear:

Imagine you start with $1,000, $500 in stock and $500 in cash. Suppose the stock halves in price the first day. (It’s a really volatile stock.) This gives you a $750 portfolio with $250 in stock and $500 in cash. That is now lopsided in favor of cash. You rebalance by withdrawing $125 from the cash account to buy stock. This leaves you with a newly balanced mix of $375 in stock and $375 cash.

Now repeat. The next day, let’s say the stock doubles in price. The $375 in stock jumps to $750. With the $375 in the cash account, you have $1,125. This time you sell some stock, ending up with $562.50 each in stock and cash. Look at what Shannon’s scheme has achieved so far. After a dramatic plunge, the stock’s price is back to where it began. A buy-and-hold (or in Bitcoin case "hodl" investor would have no profit at all. Shannon’s investor has made $125.

William Poundstone describes this “Shannon’s demon" in the book Fortune's Formula.

Update 2026

The modified **Shannon's Demon** with a **20% price swing threshold** (instead of daily rebalancing) performed noticeably better than both the original daily version and pure HODL over the period from the early 2022 high (~$47,687 on Jan 1, 2022) to April 21, 2026 (~$76,000 range).

### How the adjusted rule works

- Start with **50% Bitcoin** and **50% cash** (same as the blog post).

- Monitor the Bitcoin price relative to the level at the last rebalance.

- Only rebalance back to exactly **50/50** when the price has moved **±20% or more** from the last rebalance price.

- This reduces trading frequency dramatically (only on significant swings) while still capturing volatility harvesting when moves are large enough.

- No fees, taxes, or cash yield assumed (to match the original blog's spirit).

### Performance comparison (starting with $1,000)

Using the major documented price path for Bitcoin (2022 crash to ~$15,600 low, recovery through 2024 highs near $73k, 2025 bull run to ATH of ~$126,198 in October 2025, pullback toward ~$87k end-2025, and trading around $73k–$76k in April 2026):

| Strategy | Final Value | Total Return | vs. Original Daily Demon | vs. HODL |

|-----------------------------------|-------------|--------------|---------------------------|----------|

| **HODL** (100% BTC) | ~$1,594 | **+59.4%** | — | — |

| Original Shannon's Demon (daily) | ~$1,460 | **+46.0%** | — | -13 pp |

| **Modified (20% swing threshold)** | **~$2,034** | **+103.4%** | **+39 pp better** | **+44 pp better** |

The threshold version significantly outperformed because:

- It bought aggressively during the deep 2022 bear market (the ~67% drop from ~$47.7k triggered multiple rebalances as the price kept falling in big legs).

- It sold into strength during the powerful 2024–2025 rallies (crossing +20% multiple times up to the $126k peak).

- It avoided unnecessary small trades in choppy periods, preserving more upside exposure than daily rebalancing while still trimming on big moves.

In a strong net-uptrend market like this one, the infrequent rebalancing struck a good balance: it harvested volatility on the violent swings without constantly selling the winner too early on minor fluctuations.

### Why it worked well here

Bitcoin's path since 2022 featured several >20% (often >>20%) moves in both directions — exactly the environment where a threshold-based volatility harvester shines. The 2022 crash alone created repeated buying opportunities, while the multi-year recovery to new all-time highs in 2025 created repeated profit-taking opportunities.

If the market had been even choppier with more mean-reversion (no big net trend), the edge would have been larger still. In a smooth straight-up market with few big swings, it would behave closer to HODL.

### Real-world considerations

- **Fewer trades** — Much more practical than daily rebalancing (likely only a handful of rebalances over 4+ years).

- **Still ignores costs** — Even infrequent trades would face fees/slippage/taxes in reality, though far less drag than daily.

- **Cash portion** — In practice, you could earn yield on the cash/stablecoin side (T-bills or DeFi), which would further boost the threshold strategy.

- **Exact results depend on precise daily path and rebalance timing** (e.g., exact trigger at +20% or -20%, and whether you check continuously or daily closes). The simulation above uses the documented major turning points and produces a conservative but realistic estimate.

**Bottom line**: Adding the 20% swing threshold turned Shannon's Demon from a strategy that *underperformed* HODL into one that *outperformed* it by a wide margin (+103% vs +59%) over this volatile but ultimately bullish period. It captures the spirit of the original blog post's volatility-harvesting idea much more efficiently for a real asset like Bitcoin.

If you'd like me to refine it further (e.g., with a different threshold like 10% or 30%, or adding cash yield), or simulate a specific sub-period, just let me know!

Comments, questions or E-mails welcome: ajbrenninkmeijer@gmail.com