ETF základy
Tracking Difference and Tracking Error: What's the Difference and Why It Matters
Key takeaways
- Tracking difference (TD) is the gap between the index's annual return and the ETF's return — it shows the fund's real-world cost in practice.
- Tracking error measures how much TD fluctuates from day to day — a fund with high TE does not track its index consistently.
- A good ETF has a TD lower than its TER, because securities lending income partially offsets the TER.
- For a long-term investor, TD matters more than TER — it is the actual impact on your return.
- You can find TD and TE on JustETF or in the fund's annual reports.
Tracking difference (TD) is the annual gap between the return of an index and the return of the ETF tracking it — more precisely, how much the fund lagged (or outpaced) its benchmark index over the entire calendar period.
TD vs. TE: the confusion that trips people up
These two terms sound similar but say different things:
- Tracking difference (TD): cumulative annual return deviation. The fund earned 7.2%, the index 7.5% → TD = –0.3%. Negative TD means the fund lagged.
- Tracking error (TE): standard deviation of daily return differences. It indicates how consistently the fund tracks the index — a high TE means the fund "jumps around" relative to the index.
For the average long-term investor, TD is the more important metric: it shows the actual annual cost of the fund in practice. TE is more relevant for derivatives traders or those monitoring replication precision.
Why can TD be better than TER?
Large funds earn extra income by lending their stocks (securities lending) — they lend shares to short sellers in exchange for a fee. This income reduces actual costs below the declared TER. The result: TD can be as low as 0.05% for a fund with a TER of 0.20%. More on what TER includes in the article what TER means.
How to find TD
The most convenient way is the JustETF platform — the "Tracking Difference" tab for each fund shows historical annual figures. Alternatively, download the fund's Annual Report and compare the fund's performance against the index's performance for the same period.
TD in physical vs. synthetic replication
Synthetic ETFs tend to have very low TD because the swap counterparty guarantees the exact index performance. Physically replicated ETFs depend on the quality of trading and securities lending. Both approaches can achieve excellent TD — it depends on the specific fund. How do both replication types work? See the article on replication.
This article is educational in nature and does not constitute investment advice.
FAQ
What is tracking difference in simple terms?
The difference between what the index earned and what the fund earned over a year. If the index rose 8% and the fund 7.7%, TD is –0.3%. The closer to zero, the better job the fund is doing.
Is tracking error the same as tracking difference?
No. Tracking difference is the cumulative annual return deviation. Tracking error is a statistical measure of tracking consistency — how much the daily return gaps from the index vary. For a long-term investor, tracking difference is the more important metric.
Where do I find the tracking difference for a specific ETF?
On JustETF in the "Tracking Difference" tab for each fund. Or in the fund's annual reports — compare the fund's return to the index's return over the same period.
Can tracking difference be positive (the fund beats the index)?
Yes, and for large funds it is not uncommon. Income from securities lending can offset the TER and the fund ends up above the index. Such a fund is even more advantageous for an investor.