The Historic Automobile Group International index — known universally in the collector car market as the HAGI Top — has tracked the performance of the most significant historic automobiles since 2008. It is the closest thing the collectible car world has to a publicly available benchmark, and its data has done more to legitimise the asset class with institutional investors and family offices than any amount of anecdotal auction reportage.
Understanding what the HAGI index actually measures — and, critically, what it does not — is essential for any collector who wants to think about classic cars as investments rather than passions with financial upside.
What the HAGI Top Measures
The HAGI Top tracks 50 of the most significant collector automobiles in the world, selected based on their combination of historical importance, auction liquidity, and consistent market presence. The index is value-weighted rather than price-weighted, meaning that a car worth £5 million has five times the influence on the index reading than a car worth £1 million.
The composition is periodically reviewed, but the index has historically been dominated by pre-war Ferrari, Mercedes-Benz, and Alfa Romeo grand prix cars, post-war Ferrari road and competition models, and a smattering of significant Porsche and British marques. This composition is a crucial caveat: the HAGI Top is not measuring the classic car market as a whole. It is measuring the top tier of the most sought-after and historically significant vehicles — a subset that may bear little resemblance to what any individual collector can actually acquire.
From its inception through to 2024, the HAGI Top has recorded annualised returns of approximately 8 to 12 percent depending on the specific period measured, outperforming the S&P 500 in several rolling 10-year windows and broadly matching it in others. The headline figure is impressive. The nuance matters more.
The Dispersion Problem
The single most important thing the HAGI data conceals is dispersion — the degree to which individual car performance varies around the mean. The index is an average, and averages in thin, illiquid markets can be profoundly misleading.
Within the collector car market, studies of auction data suggest that the top 10 percent of transactions by value account for a disproportionate share of total appreciation. This means a small number of exceptional cars — typically those with unimpeachable provenance, race history, or celebrity ownership — drag the average upward, while a much larger number of technically eligible cars deliver flat or negative real returns.
The 2008–2012 period illustrates this sharply. Whilst the HAGI Top fell approximately 35 percent from its 2008 peak (collector cars were not immune to the financial crisis), certain pre-war Ferrari and grand prix Mercedes models held their value almost entirely. Collectors who owned those specific cars experienced a very different reality from those holding mid-tier GT cars or European touring cars that had been swept up in the pre-crisis enthusiasm.
What Actually Delivers Returns: The Evidence
Analysis of auction records from Bonhams, RM Sotheby’s, Gooding & Company, and Artcurial over the past 20 years points to consistent patterns in which car categories outperform.
Competition history trumps specification. A Ferrari 250 GT that raced at Le Mans in 1961 consistently outperforms a mechanically identical example with no competition history, often by margins of 40 to 100 percent. The market pays for narrative, and verifiable racing provenance is the richest narrative available. Documentation — period photographs, entry forms, technical inspection sheets, and ideally the car’s original logbook — determines how much of that premium a seller can extract.
Single-family ownership history. Cars with a short, traceable ownership chain — ideally two or three custodians over their entire life — command premiums over those with complex or fragmented histories. A 1963 Aston Martin DB5 with three owners, all documented, that has been in the same collection for 25 years will outperform an equivalent car with 12 recorded owners by a meaningful margin at auction.
Matching numbers and original specification. Across virtually all marques and periods, cars retaining their original engine, gearbox, and body specification consistently outperform restored or modified equivalents. The premium for matching numbers has widened significantly since 2010, as the collector community has become more sophisticated. A numbers-matching 1967 Ferrari 275 GTB/4 commands perhaps 30 percent more than an otherwise identical car with an engine transplant, and that gap has grown over time.
Marque matters, but period matters more. Ferrari outperforms the broader market at the index level, but Ferrari’s own performance is widely dispersed. 1950s and 1960s V12 competition and GT cars have significantly outperformed 1980s and 1990s production Ferraris. The 308 and Mondial, once the entry point for new collectors, have delivered near-zero real returns over 20 years. Meanwhile a 1966 Ferrari 206 S Dino Competizione set auction records at nearly every sale between 2015 and 2023.
The Costs That Kill Returns
Retail investors studying the HAGI Top often forget that it measures gross price appreciation — it does not subtract the costs associated with actual ownership. These costs are substantial and, in aggregate, can convert a nominally appreciating asset into a flat or negative real-return investment.
Storage, properly done — climate-controlled, secure, with appropriate air circulation and tyre support — costs between £3,000 and £8,000 per year per car depending on facility. Insurance through specialist providers such as Hagerty or AXA Art adds 0.5 to 1.5 percent of agreed value annually. Maintenance for a running, driveable car includes periodic mechanical recommissioning, tyre replacement, and occasional restoration expenditure. A pre-war car requiring significant restoration can easily absorb £100,000 to £400,000 of spend before returning to market — costs that must be recouped in the sale price to deliver any return.
Auction houses charge 5 to 12 percent buyer’s premium and 5 to 10 percent seller’s commission, meaning a round-trip through auction carries total transaction costs of 10 to 22 percent of the hammer price. This alone requires meaningful appreciation to break even.
The Informed Collector’s Approach
The evidence suggests that treating classic cars as a pure investment — buying and holding purely for financial return — is a sophisticated undertaking that most investors approach with insufficient rigour. The collectors who consistently outperform buy cars with compelling, verifiable stories; maintain them with documented, specialist care; and hold them for 8 to 15 years to absorb transaction costs and allow the narrative to compound.
More importantly, the most successful collector-investors describe their holdings as assets they happen to enjoy. The car that sits in climate-controlled storage and is never driven is the car that deteriorates mechanically, loses the patina of authentic use, and often fetches less at auction than an equivalent example with light, appropriate mileage. The market has become sufficiently sophisticated to distinguish between a car preserved in use and a car frozen in neglect.
The HAGI index points directionally at an asset class with legitimate investment merit. What it cannot point to is the specific car, at the specific price, acquired with the specific documentation that actually delivers the return. That remains the collector’s art — and no index has yet found a way to replicate it.
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