Does that just mean that they do their own execution, or does it mean that their short-holding-time strategies are a major profit center?

FWIW, Cliff Asness disagrees with you:

> we are not high-frequency traders

https://www.aqr.com/Insights/Perspectives/High-Frequency-Der...

I understand he does, but our definitions are different. Firstly, they are not a buy-and-hold sort of fund. Their strategy is more momentum based, and in my experience, to be good at that you need a deep understanding of HFT in current market conditions. I'm not saying they're market makers, but I will say that they employ some sub-minute strategies - to me, that is high frequency (not super high frequency, but high frequency nonetheless).

Also, they seem to hire a fair few ex-HF guys in senior positions (e.g. https://nypost.com/2015/07/31/aqrs-head-of-trading-on-paid-l...)

To be clear, when you say AQR is primarily a "high frequency" firm, do you mean they are mostly position neutral with execution in (at most) a few microseconds?

I do not think HFT has a very clear definition anyways. I'm pretty sure most we hear of comes from regulatory cases/exposure.

This is how the SEC characterizes HFT firms.

1. Use of extraordinarily high speed and sophisticated programs for generating, routing, and executing orders.

2. Use of co-location services and individual data feeds offered by exchanges and others to minimize network and other latencies.

3. Very short time-frames for establishing and liquidating positions.

4. Submission of numerous orders that are cancelled shortly after submission.

5. Ending the trading day in as close to a flat position as possible (that is, not carrying significant, unhedged positions overnight).

From pages 4-5 https://www.sec.gov/marketstructure/research/hft_lit_review_...