What it means to build a rules-based portfolio in an asset class where almost nothing is standardised.
The word index implies rules. In listed markets those rules are unremarkable: a universe, an eligibility screen, a weighting scheme, a rebalancing calendar. Applying the same discipline to collectibles is harder, because the universe is not enumerated and the constituents do not trade continuously.
Eligibility before selection
The design intention is that an asset must clear documented criteria before anyone considers whether it is desirable. Market depth, historical significance, grading quality, transaction frequency, collector demand and pricing reliability are screens, not preferences. An asset that fails them is not eligible regardless of how attractive it seems.
Limits that bind
- —Caps on exposure to any single subject, so no index becomes a bet on one career.
- —Caps by era, so the portfolio is not implicitly a vintage or a modern fund.
- —Caps by price band, so a small number of large positions cannot dominate valuation.
- —Documented replacement rules, so removing an asset is a procedure rather than a judgement call.
Rules before discretion. The point of writing the methodology down in advance is that it constrains you later.
None of this eliminates risk, and none of it has yet been implemented. No index has been constructed and no asset has been acquired. What a published methodology does is make the eventual portfolio auditable against something other than the constructor's own account of their reasoning.