Every day, every minute of trading, investors can look to popular indices and data points to determine how markets are performing. Equity investors consult the S&P 500 or the NASDAQ Composite. Fixed-income investors check the status of the 10-year Treasury bond and various credit spreads. For collectors, understanding the performance of their chosen markets isn’t as simple.

However, with the proliferation of data and a growing interest in collectibles, various collectible market businesses have created indices to provide collectors with a better sense of the market environment.

What is a collectible market index?

Just as the S&P 500 monitors the performance of 500 underlying companies in the United States, collectible market indices track the fluctuations in value of an underlying assortment of collectible assets. In most cases, collectible market indices represent and track a specific category of assets. For instance, there are specific indices tracking wine, art, and trading cards, respectively, rather than a mixed assortment of these assets collectively.

The selection of underlying assets in an index is made at the discretion of the party building and maintaining it. That might be a third-party data platform or a marketplace where the asset is bought and sold. The intent in selecting assets is typically to build a group that represents a specific type of collecting, like wines from Burgundy, vintage sports cards, or Rolex watches.

As with equity indices, the value of the index fluctuates with the prices of its underlying constituents. The extent to which an underlying asset influences the broader index depends on the methodology used to maintain the index; the assets might be equally weighted within the index or weighted by price, for example. In the latter case, changes in the price of the most expensive assets would have the largest impact on the index.

What are the strengths and weaknesses of indices tracking collectible markets?

Collectible indices are ultimately only as accurate as their underlying data. In collectibles, data is often fragmented, and many sales occur privately at unknown prices. These factors can impede the creation of a robust and representative index. Additionally, the indices maintained by marketplaces often capture only the sales that take place on that platform, resulting in a narrower dataset that is potentially less representative of the broader market.

Choices in methodology can also draw criticism.

Some of the respected indices that track the fine art market use a methodology based on the Case-Shiller Repeat Sales method commonly deployed in real estate. Without getting into the finer points of this methodology, it effectively measures the evolution of the market based only on those works for which we have multiple sales data points, or “repeat” sales. Proponents of this methodology feel it’s appropriate for fine art, a category in which every original piece is largely unique, because it measures the performance of specific artworks (rather than median or average prices). Detractors will note, however, that this methodology has an inherent survivorship bias that could skew the index performance upward; the index only includes artworks that sell successfully at auction on multiple occasions, effectively ignoring all those that fail to sell.

Meanwhile, those indices that track a specific artist or category based on the average or median value of works sold during a period suffer different shortcomings. The fluctuations in that index will be highly dependent on the caliber of paintings coming to work in each period. Consider a simplistic example where a Monet sells for $60 million in one period, and a different Monet sells for only $30 million in the next. An index based on average sales price would fall considerably, even if the $30 million result was actually a great sales price for that specific work and indicated an appreciating market.

Those indices that draw on the largest breadth and depth of sales data, measuring assets that trade frequently, will usually offer the most current and representative information on the performance of a category. However, that’s easier said than achieved. Still, price data and indices are more prevalent and accessible today than ever before, positioning collectors to more readily understand their markets without dedicating painstaking research or relying unduly on anecdotal data. So, while they should be aware of potential shortcomings and biases, they can still benefit from consulting indices, even if through a critical lens.

What indices can collectors follow in each collectible category?

While this is not meant to be an exhaustive list, below are an assortment of indices that collectors may find helpful in each collectible category, along with some background information on each.

Art

In art, many indices have found shelter behind paywalls or in private hands. Take, for example, the Mei-Moses indices, which track auction sales throughout several decades and use the Case-Shiller Repeat Sales methodology to represent performance. Sotheby’s acquired those indices in 2016, and their up-to-date status is rarely available to the public. Similarly, ArtNet’s indices, based on its extensive database of sales, are available only to paid subscribers.

Paid tools may be well worth the money for high-net-worth collectors spending handsomely in a category, but when a quick glance will suffice, there are other options available.

Art Market Research

Art Market Research offers an “All Art” index dating back to 1978, which uses a sample of auction sales from top auction houses to derive an average value for each artist in their database. Those averages are calculated among all sales in a rolling, 24-month period, with a greater weighting given to more recent sales. The averages, known as Artist Prices, are then totaled to an Underlying Monetary Value, forming the basis for the index value.

This method, using average values at auction during a period, has its flaws, as thinly traded artists may see their prices influenced by the caliber of works coming to auction. Additionally, weighted-average prices over a period may fail to capture nuances in the types and caliber of artworks that have appeared for sale, which could result in an inaccurate representation of market performance.

Still, the index is a robust and thoughtfully developed offering that captured the sharp post-pandemic rise and fall of the market.

ArtPrice

ArtPrice shares its ArtPrice100 index of blue-chip artists publicly, representing the 100 most-traded artists by volume that meet a liquidity criterion of 10 works sold at auction each year. Each artist’s weighting is based on their average volume of sales over the last five years, and the index is rebalanced annually. As of the end of 2024, the most represented artist was Pablo Picasso, with a weighting close to 7.8%. The index tracks the annual price performance of each artist at auction, which can be shaped by the type and caliber of works sold. However, the diversification among 100 artists can smooth outsized swings in value.

Like AMR, the ArtPrice100 captures recent fluctuations in the market, as well as episodes of historical challenges.

LiveArt

LiveArt is a peer-to-peer marketplace for fine art with a robust set of analytics. Its indices differ from those previously mentioned, as evolutions in index value are based on changes in the LiveArt Estimate for each work, rather than on sales prices. Of course, sales prices impact those proprietary estimates, which are produced with the help of AI. This choice tends to result in smoother indices less prone to boom and bust movements based on specific auction events.

However, viewers will quickly note that the various indices show significantly tamer price movements in recent years relative to other indices more directly impacted by recent auction results. That doesn’t mean it’s the wrong approach or inaccurate, merely different and perhaps a counter to many of the sky-is-falling headlines on the art market in recent months.

Cars

Hagerty Collector Car Indexes

Hagerty began as an insurance agency for collector cars before expanding into a membership platform offering auctions, a marketplace, valuation tools, price guides, and even indexes. Hagerty’s Price Guide Indexes are updated on a quarterly basis in step with the company’s Price Guide values for collector cars. Offered indexes include everything from British Cars, to Ferraris, to Trucks & SUVs.

The indexes average the prices of the underlying collector cars, which are based on Hagerty’s Price Guide, specifically the condition #2 (“excellent”) values for each vehicle. Hagerty determines its Price Guide values based on several sources, including auction results, peer-to-peer sales, asking prices, and dealer and broker sales. As a prominent insurer, the company has unique access to data on sales prices when customers remove cars from their policies. Hagerty then relies on a team of contributors to evaluate these sources and propose changes to Price Guide values, which are peer reviewed before being approved or reconsidered.

Many of the indexes date back as far as 2006, offering collectors a lengthy period for evaluation. While updates are only quarterly, that cadence is sufficient to understand material market movement over time. Hagerty provides information on the underlying components of each index, along with each car’s Price Guide value and associated price movement. Users will note that the selection of components is subjective based on Hagerty’s evaluation of which cars are most “sought-after” in each category, and the number of components is often fairly limited, with no index exceeding 25 cars. This may result in a limited picture of each category, though the data is directionally helpful nonetheless.

Sports & Trading Cards

CardLadder Indexes

CardLadder is a trading card database that aggregates and organizes trading card sales data from a number of prominent industry marketplaces and platforms. The CardLadder team vets sales for legitimacy and adds those sales to a specific card profile or “Ladder.” Using that data, CardLadder creates a variety of indices to track specific subsets of the trading card market. In some cases, CardLadder hand-picks the index constituents; one such example is the CardLadder 50, which is meant to be a subset of 50 cards that best represent the market. In others, like the sport or era-based indices, the indices include all cards in the database that meet the relevant criteria; for instance, the Vintage index includes all cards released between 1946 and 1983.

CardLadder employs a methodology similar to the S&P to build its indices, with higher-priced cards receiving greater weight. For inclusion, cards must sell at least twice in the last year and once in the last six months. The indices are limited to the cards for which CardLadder has created Ladder profiles, which may represent a reduced portion of the tradable universe. The indices are also subject to historical revision as new cards are added to the database.

Watches

WatchCharts Market Indexes

WatchCharts is a source of watch market data, collecting and analyzing watch market prices across platforms to provide price guides and indexes encompassing over 28,000 watches. They offer an assortment of indexes, including:

• An Overall Market Index – Tracks overall market trends using 30 watches each from the 10 biggest brands that WatchCharts tracks on the secondary market.
• Brand Indexes – Tracks the top 30 watches for a specific brand (Rolex, Patek Philippe, etc.).
• Brand Group Indexes – Tracks the top 30 watches for each brand in a specific ownership group (LVMH, Swatch, etc.).
• Price Range Indexes – Tracks the performance of watches in specific price bands ($5k to $10k, $10k to $20k, etc.).

WatchCharts selects watches for any given index based on its market share in that category. So, the Rolex watch that represents the largest portion of the total annual transaction value in WatchCharts’ Rolex dataset would be included in the Rolex index at the highest weight. Currently, that’s the Rolex Datejust 126334, which makes up 8.2% of the Rolex index.

The limitations of the approach are similar to those for other indices. Data on confirmed sales can be elusive or misleading; where necessary, WatchCharts might use a dealer’s asking price, which can differ from the ultimate sales price. Additionally, a watch’s condition is a subjective factor that is difficult to quantify, which may result in some sales producing prices that are outliers relative to the market.

Subdial Watch Index

Subdial is an online platform that enables the buying and selling of luxury watches, while also providing market data and indices. Its flagship index is created in partnership with Bloomberg and tracks a list of 50 references with the largest traded value (or volume, as with WatchCharts). The index is rebalanced annually. However, as there’s no limit to the number of watches from one brand that can be included in the index, it’s quite Rolex-heavy.

Like WatchCharts, Subdial provides brand-specific indices as well, and users can view the performance in GBP or USD (Subdial is London-based). In selecting watches for inclusion, Subdial ensures they meet a liquidity standard, meaning they trade frequently enough for the data to be useful and representative. They also grapple with similar data issues to WatchCharts, where a final sale price may be difficult to determine from a dealer’s listed price. To account for this reality, the Subdial team uses data to discount the dealer prices based on factors like the watch model and how long it was available for sale.

The indices from WatchCharts and Subdial can be used in tandem to get a reliable directional understanding of the watch markets, though some nuances in methodology can cause differences in specific numerical performance.

Wine & Spirits

Liv-Ex Indices

Perhaps the best-known and most widely cited wine indices, Liv-Ex indices have been in production since 2004. Liv-Ex is a global fine wine exchange conceived for businesses to buy and sell amongst each other. The indices include the flagship Liv-Ex Fine 100, which tracks 100 of the most sought-after wines on the secondary market, as well as smaller regional indices like the California 50 and the Bordeaux Legends 40.

Each index tracks the movement of an underlying set of wines that meet qualifying criteria based on trading volume and value. The price of each underlying wine is based on the mid-point between the highest bid and the lowest offer on the Liv-Ex platform. This means the data comes exclusively from Liv-Ex, and it does not rely solely on list prices, which is a common practice among other providers and does not necessarily approximate executed transactions.

Cult Wines Indices

CultX is a next-generation fine-wine trading platform that allows users to build, track, and manage fine wine portfolios. Their indices are powered by data from Wine-Searcher, an extensive database and search engine of wine and spirits, with 17 million product listings. Indices are rebalanced based on liquidity criteria and activity on Wine-Searcher, while underlying prices are based on price offers on Wine-Searcher.

Like Liv-Ex, Cult Wines has a Global Index, as well as several regional offerings. Their site offers a longer time series of data to free users, with data downloads also available.