About CBX

CBX — the Collectible Brick Index — publishes transparent, rules-based benchmarks for the secondary market in retired LEGO^® sets and minifigures. The goal is simple: give collectors and the merely curious an honest, well-documented way to see how slices of the retired market have moved over time — with nothing hidden behind a black box.

What an index is here

Each index tracks a defined basket of items. Levels are price-weighted (larger-value items carry more of the basket, Dow-style), rebalanced monthly, and set to a base of 1,000 at inception, so a single number shows how that slice of the market has moved. Every constituent, its weight, and the exact selection rules are published on the index's factsheet — there is no editorial discretion once the rules are set.

Independence

This is an independent project. It is not affiliated with, sponsored by, or endorsed by the LEGO Group. “LEGO” is a registered trademark of the LEGO Group; it is used here only to refer factually to the products the indices track.

Where the data comes from

• BrickLink — secondary-market prices for sets, minifigures, and parts.
• Brickset — catalog reference: themes, release years, piece and minifig counts, retail price, and retirement status.
• U.S. Bureau of Labor Statistics (CPI-U) — the inflation series used to translate nominal figures into real, inflation-adjusted terms.

Prices are market-value estimates, not appraisals or transaction guarantees, and can move quickly. Historical levels before the live inception date are modeled from the available history and are labelled as such on each chart.

Corrections & contact

Spotted an error in a constituent, a price, or the methodology? We would genuinely like to know — corrections keep the numbers honest. See How the indices work for the full methodology, or reach out via the contact address published in the footer.

Nothing on this site is investment advice, an offer, or a solicitation to buy or sell anything. Figures are for informational purposes only.

How the indices work

Every index follows the same published, mechanical rules. This page explains those rules end to end, answers common questions, and defines the terms used across the site.

Methodology, step by step

1. Selection. Each index has an explicit rule for what belongs in it — for example, the 100 most valuable retired sets, or every set within a given theme. The rule is stated on the factsheet and applied without exception.
2. Pricing. Constituents are valued from BrickLink secondary-market data, BrickLink-first and US-scoped. We prefer the quantity-weighted average of recent New sales; when sold data is thin we fall back to the trimmed median of the few lowest current US New listings (widening to North America, then worldwide, only if none are closer), so VAT- and shipping-inflated international asks don’t distort the figure. To keep quotes honest a set needs at least two active listings to enter an index, while an existing constituent may remain on a single listing so a genuinely scarce set isn’t churned out the moment its lone listing lapses.
3. Weighting. Indices are price-weighted: each constituent's share of the basket is proportional to its price, so more valuable items move the index more. This mirrors the classic Dow construction.
4. Rebalancing. Baskets are refreshed monthly. Constituents that no longer meet the rule drop out; newly eligible items enter. A divisor adjustment keeps the level continuous across rebalances so changes reflect the market, not the reshuffle.
5. Base level. Each index starts at 1,000 on its inception date. A level of 1,250 means the basket is up 25% since inception.
6. Inflation adjustment. Returns are shown in both nominal and real (inflation-adjusted) terms using BLS CPI-U, so growth can be separated from the general rise in prices.
7. Modeled history. For months before an index went live, levels are modeled from available historical value estimates and clearly shaded as modeled on the charts. Everything from the live inception date forward is computed from stored month-end snapshots.

Frequently asked

Glossary

Index level

The single number tracking a basket, rebased to 1,000 at inception.

Constituent

An individual set or minifigure that is a member of an index.

Price-weighting

A weighting scheme where each constituent's influence is proportional to its price.

Rebalance

The monthly process of refreshing an index's membership and weights against its rule.

Nominal vs. real

Nominal is the raw change; real strips out inflation (via CPI-U) to show purchasing-power change.

CAGR

Compound annual growth rate — the smoothed annualized rate of change over a period.

MSRP

Manufacturer's suggested retail price — the original launch price, used as a baseline for returns.

Part-out value

The estimated value of a set if sold as individual parts and minifigures.

Nothing on this site is investment advice, an offer, or a solicitation. Figures are informational estimates derived from third-party data and may contain errors.

Privacy Policy

Last updated: August 27, 2026

This Privacy Policy explains how CBX (“we,” “us,” the “Site”) handles information when you visit. CBX is an independent, informational project and is not affiliated with, sponsored by, or endorsed by the LEGO Group.

1. The short version

We run a read-only informational site. We do not require an account, and we do not ask you for personal information to browse. We collect only the minimal technical data needed to operate the Site and, if enabled, privacy-preserving aggregate analytics. We show third-party ads through Google AdSense, which may use cookies to serve and measure ads (see “Advertising” below). We do not sell your personal information for money.

2. Information we collect

• Information you choose to give us. If you email us (for example, to report a data error), we receive your email address and whatever you include in your message. We use it only to respond.
• Technical data collected automatically. Like most websites, our hosting provider records standard server logs (e.g., IP address, browser/user-agent, pages requested, timestamps) for security, debugging, and abuse prevention.
• Analytics (if enabled). We may use a privacy-preserving, cookieless analytics tool that reports aggregate, non-identifying usage (e.g., page views). It is not used to build profiles of individuals.
• Cookies & advertising. The Site’s own code sets no tracking cookies. However, we display ads via Google AdSense, and Google and other third-party vendors may set advertising cookies or use similar technologies to serve and measure ads (see “Advertising” below). When you click an outbound “buy” link, the destination (e.g., eBay, Amazon) may also set its own cookies under its own privacy policy — see “Affiliate links” below.

3. How we use information

To operate, secure, and improve the Site; to respond to messages you send us; and to comply with legal obligations. We do not use your information for automated decision-making that produces legal effects.

4. Affiliate links

Some outbound links are affiliate links (e.g., eBay Partner Network, Amazon Associates). If you click them, those third parties may set cookies or collect information to attribute a referral. We may earn a commission on qualifying purchases at no extra cost to you. Their data practices are governed by their own privacy policies, not ours.

5. Advertising (Google AdSense)

We display ads through Google AdSense to help keep this site free. Google is a third-party vendor and, together with other ad partners, may use cookies and similar technologies to serve and measure ads.

• Third-party vendors, including Google, use cookies to serve ads based on your prior visits to this and other websites.
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For details on how Google handles data on sites that use its services, see How Google uses information from sites or apps that use our services.

6. Service providers we rely on

We share limited data only with providers that help us run the Site, including:

• Hosting: Render, Inc. (serves the Site; processes server logs).
• Advertising: Google AdSense (serves and measures ads; may set cookies or use identifiers, subject to your consent where required).
• Analytics (if enabled): a privacy-preserving, cookieless analytics provider.
• Payments (only if and when enabled): Stripe, Inc. would process any payments; we would not store full card details.

We do not sell your personal information for money. Depending on your consent and settings, our advertising partners may use cookies or identifiers to personalize ads; some U.S. state privacy laws treat this as “sharing” (or a “sale”) for cross-context behavioral advertising. You can opt out as described in “Advertising” above.

7. Data retention

We keep server logs and any correspondence only as long as needed for the purposes above or as required by law, then delete or anonymize them.

8. Your rights

Depending on where you live (e.g., the EU/UK under GDPR, California under CCPA/CPRA), you may have rights to access, correct, delete, or restrict processing of your personal information, and to object or complain to a regulator. To make a request, contact us at support@cbxindex.com. We will respond as required by applicable law. We do not discriminate against you for exercising these rights.

9. International visitors

The Site is operated and hosted in the United States. If you visit from another country, your information may be processed in a country with different data-protection laws than yours.

10. Children’s privacy

The Site is intended for a general, adult audience and is not directed to children under 13 (or the minimum age in your jurisdiction). We do not knowingly collect personal information from children. If you believe a child provided us information, contact us and we will delete it.

11. Security

We take reasonable measures to protect the limited information we handle, but no method of transmission or storage is completely secure.

12. Changes to this policy

We may update this policy from time to time. Material changes will be reflected by updating the “Last updated” date above.

13. Contact

Questions or privacy requests: support@cbxindex.com.

Informational only. Nothing here is legal or investment advice.

Terms of Use

Last updated: August 25, 2026

Please read these Terms carefully. By accessing or using CBX (the “Site”), you agree to them. If you do not agree, do not use the Site.

1. What the Site is

CBX publishes transparent, rules-based informational benchmarks for the secondary market in retired LEGO^® sets and minifigures, built from third-party data. It is provided for general information and educational purposes only.

2. Not investment advice

Nothing on the Site is investment, financial, tax, or legal advice, and nothing on the Site is an offer, solicitation, or recommendation to buy or sell any item, security, or asset. The “indices” are informational measures, not funds, securities, or investment products, and cannot be purchased. You are solely responsible for any decisions you make. Do your own research and consult a qualified professional before making financial decisions.

3. No warranty; accuracy of data

The Site aggregates and derives figures from third-party sources (including secondary-market price data and catalog data) and from modeled estimates. Data may be delayed, incomplete, or inaccurate, and historical figures before an index's live inception are modeled. The Site and all content are provided “as is” and “as available,” without warranties of any kind, express or implied, including accuracy, completeness, merchantability, or fitness for a particular purpose.

4. Trademarks and non-affiliation

LEGO^® is a registered trademark of the LEGO Group. The LEGO Group does not sponsor, authorize, or endorse this Site, and this Site is not affiliated with the LEGO Group. Product names and marks are used only to refer factually to the products the benchmarks track. All other trademarks are the property of their respective owners.

5. Intellectual property

The selection, arrangement, methodology, text, and presentation on the Site are ours and are protected by applicable law. Underlying prices, catalog details, and images originate with third parties and remain the property of their respective owners. You may view and share links to the Site for personal, non-commercial use. You may not copy, scrape, harvest, redistribute, or commercially exploit the Site's data or content without our prior written permission.

6. Acceptable use

You agree not to: use automated means to scrape or bulk-download the Site; attempt to disrupt, overload, or gain unauthorized access to the Site or its systems; or use the Site in violation of any law. We may limit or terminate access for misuse.

7. Affiliate links and third-party sites

Some outbound links are affiliate links, and we may earn a commission on qualifying purchases at no extra cost to you. The Site may link to third-party sites we do not control; we are not responsible for their content, products, availability, pricing, or practices, and your use of them is at your own risk.

8. Limitation of liability

To the fullest extent permitted by law, we will not be liable for any indirect, incidental, consequential, special, or punitive damages, or for any loss arising from your use of, or reliance on, the Site or its data. Our total liability for any claim relating to the Site will not exceed USD 100 or the amount you paid us, if any, in the 12 months before the claim.

9. Changes

We may modify the Site or these Terms at any time. Continued use after changes take effect constitutes acceptance. Material changes will be reflected in the “Last updated” date.

10. Governing law

These Terms are governed by the laws of the United States and the operator's state of residence, without regard to conflict-of-law rules.

11. Contact

Questions about these Terms: support@cbxindex.com.

Informational only. Nothing here is legal or investment advice.

References & research

Independent academic work has studied the retired LEGO^® secondary market as an alternative asset class. We collect the most relevant peer-reviewed research here as background — to show that the questions these benchmarks measure have been examined seriously in the finance literature. We link to the original sources rather than rehost them; citing this work does not imply the authors endorse this site.

Primary study

How this relates to what we do

Our indices measure the same underlying market this research examines — prices of retired sets on the secondary market — but they are our own transparent, rules-based construction, independently calculated and not affiliated with the study or its authors. Where the paper looks back at a fixed sample, our benchmarks track the market on a rolling, fully disclosed basis. See How the indices work for our methodology.

External research is provided for background and educational context only. It is not investment advice, not a recommendation, and not an endorsement of this site by any author or publisher. Historical results describe the past and do not predict future returns.

What should we build next?

CBX grows from what collectors actually want to see. Suggest a new index, a theme we don't cover yet, a feature, or flag a data problem — it goes straight to our roadmap list, and every entry gets read.

Prefer email? Reach us any time at support@cbxindex.com.