Apex: An Explanation

APEX RATINGS (Annual Progeny Earnings IndeX)

APEX Ratings were designed to address a couple of important problems or limitations of the Average-Earnings Index. (AEI), which had been developed by The Blood-Horse magazine in the 1950s. The AEI is calculated based on earnings in a single year or (Southern Hemisphere) season; the basic idea is you take all runners by all sires and divide their total earnings by the number of runners to establish what earnings equal an index figure of 1.00. For example, if 50,000 runners earn $1-billion, the average earnings per runner would be $20,000 which would then equal 1.00. If a sire has, say, average earnings per runner of $40,000, his average earnings index would be 2.00. The Cumulative Average-Earnings Index (CAEI) extends that calculation over multiple years.

Two big problems: If a sire has 100 runners earn, say $7-million in a season but $6-million of it came from one horse in the Dubai World Cup, the sire's AEI for that year would be 3.50 whereas, in reality, the other 99 horses would make the sire's AEI more like 0.50. APEX ratings address that issue. The other big problem comes from taking a sire's whole career (CAEI) as a guide. There are numerous examples of once-great sires tailing off in their later crops; Gone West and Green Desert are two recent examples. The stats might say a sire has a CAEI of 2.25, but when you break it down, sometimes they were 3.00 early and 1.50 late.


APEX Ratings are indexes which measure the frequency with which sires get runners which achieve specified earnings thresholds in each jurisdiction measured. These classifications are:

A Runners: top 2% of earners from all runners in a calendar year or racing season;
B Runners: next 2% of earners;
C Runners: next 4% of earners;
ABC Runners are therefore the top 8% of earners (A+B+C Runners)

Each sire rated is assigned 17 different indexes:

Overall A Runner Index
Overall B Runner Index
Overall C Runner Index
Overall ABC Runner Index
A, B, and C Runner Indexes for each of three Regions (9 total):

North America (USA and Canada combined);
Europe (UK and Ireland combined; France; Germany)

ABC Age Ratings for 2yo's; 3yo's; 4yo's; and 5yo's and Up (4 total)

Do please note that APEX ratings are based, like the AEI, on annual earnings. As such, a horse must be counted as a separate runner (designated a 'year-starter') each year it runs. Similarly, a horse can be an A Runner etc. every year it reaches or exceeds the 'A Runner' earnings threshold. In APEX (see below), that is limited to seven years.


Seven different countries are included in the Northern Hemisphere ratings:

US and Canada (2 countries) are combined into the region of North America.

UK and Ireland (2 countries), France, and Germany are combined into the region of Europe. The raw numbers are calculated for each of the three 'earnings jurisdictions' (UK/Ireland; France; Germany) and added together to compose 'Europe'

Japan (JRA races).


Another issue with the AEI is that, by being mathematically 'pure' and including all runners by all sires, the inclusion of a certain percentage of absolute no-hopers bred in the back of beyond has a tendency to inflate sires' ratings from the perspective of the 'commercial' market. Sires with an AEI of 1.00 are in fact below average; we estimate a 1.40 AEI is actually an 'average' sire from a commercial perspective.

Our answer was to eliminate sires with fewer than 10 named 3-year-olds of the last year covered by our analysis (so, for 2017, they had to have 10+ foals of 2014 to be included). It is not as mathematically pure, but it's a lot more practically useful, which is a principal objective of APEX. It means when you see a sire has any APEX index of 1.00, it means he really is average in the world in which we are actually working.

Secondly, we limited the years for which we calculate ratings to the last seven years, so, for 2017, that is 2011-2017. Again, we don't produce a Career figure if they had runners before then, but our objective is practical application, not an historical summary. We do have ways we do that, but the objective of APEX figures is for them to be applicable and useful to participants in the commercial auction marketplace.

Click here to return to the APEX page.


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