On 9 October 2026, two companies made up 94.5% of the market value in the CoinBucha Listed Bitcoin Index: SpaceX and Tesla. Each of them holds bitcoin worth about 0.1% of its own market value.

So an index meant to follow listed companies that hold bitcoin was, in practice, following a rocket company and a car company. We changed the rules two days later. This is what went wrong, the rule we wrote, and what it did.

How it happened

The index weights companies by market capitalisation. Under the old rules (methodology 1.x), any listed company with a sourced bitcoin holding could be admitted, and the 20% cap on a single company was only a display view: the published level itself was not capped.

Admit two of the largest companies in the world because they hold a small bitcoin treasury, and they swallow the index. Nothing in the data was wrong. The rule was.

The rule we added (R6, dated 11 October 2026)

A company is now admitted only if it is one of two things:

  • A bitcoin business (Rule A). At least 50% of its latest fiscal-year revenue, as reported in its own annual filing, comes from bitcoin mining, bitcoin mining hardware, or exchange, brokerage or custody where bitcoin is a material asset. A business built on another chain's token does not qualify, whatever its size.
  • A material holder (Rule B). It holds at least 1,000 BTC, and that holding is worth at least 30% of its market capitalisation at the review. Once in, it leaves only if the same measure falls below 20%. A reading above 300% admits nothing by itself and sends the record back for a check.

And the 20% single-company cap now binds in the level itself, through capping factors set at each review.

What it did

Of the 32 constituents, 28 pass:

  • 6 on Rule A alone: Coinbase, Hut 8, Riot Platforms, Ionic Digital, Bitdeer, Keel Infrastructure
  • 15 on Rule B alone
  • 7 on both measures

Four leave: SpaceX (bitcoin = 0.1% of its market value), Tesla (0.1%), Block (1.6%), Core Scientific (1.4%). Their company pages stay in the register, with the reason.

The bitcoin barely moved: 1,163,627 of the constituents' 1,203,813 BTC (96.7%) is still in the index.

Why we re-based instead of chaining

The old series was three weeks old and nobody cited it yet, so we chose a clean start over chaining a series whose composition we now reject. The index is re-based to 100 on 9 October 2026, the last close before the decision. The 1.x series is closed, not revised: no old figure was changed. The whole change is one dated entry in an append-only corrections log.

From now on, a methodology change takes effect at a pre-announced close. This first one took effect on publication, because nobody outside depended on the series yet.

Same companies, two answers

There are two series on the same 28 companies and the same base date:

  • LBTC weights by market capitalisation, capped at 20% per company.
  • LBTC-H weights by bitcoin held. Strategy holds about 73% of the constituents' bitcoin, so it carries about 73% of LBTC-H.

Neither is "right". They answer different questions: how the listed bitcoin companies are valued, and where the bitcoin actually sits.

Check it yourself

Rule B is computed on every row from three numbers you can see: the company's holding, the BTC-USD reference close for the review date (82,546.32 on 9 October 2026), and its recorded market capitalisation. Rule A cites each company's own annual filing on its row.

If you want the monthly read (which companies moved the index, who bought or sold bitcoin according to their filings), the free Bitcoin Stocks Monthly Brief is one email a month.

Information, not financial advice.