I have downloaded the dukascopy historical tickdata from
https://www.dukascopy.com/swiss/english ... istorical/

Below is what I get for 2016 November 1st. The second 0 of the day has 3 ticks, the second 1 of the day has only 1 tick (at 948 milliseconds past the second number 1)... etc... This seems a little sparse.

Date HHMMSS.fff Ask Bid AskMIO BidMIO
1/11/2016 0.049 1.09710 1.09708 1.5 1.649999976
1/11/2016 0.403 1.09710 1.09706 1.690000057 6.599999905
1/11/2016 0.937 1.09708 1.09705 1 3.75
1/11/2016 1.948 1.09709 1.09705 1.120000005 3.75
1/11/2016 4.039 1.09708 1.09705 1 3.75
1/11/2016 5.26 1.09708 1.09706 1 1.25
1/11/2016 5.805 1.09708 1.09705 1 4.5
1/11/2016 7.577 1.09710 1.09705 3.940000057 3.940000057
1/11/2016 11.191 1.09708 1.09705 1 3.75
1/11/2016 17.26 1.09709 1.09705 1.120000005 1
1/11/2016 21.46 1.09706 1.09704 1 6.75
1/11/2016 21.762 1.09703 1.09700 1 1.120000005
1/11/2016 21.966 1.09701 1.09697 1 1.5

I compare this with data from Pepperstone downloaded from:
https://pepperstone.com/en/client-resou ... -tick-data

The data is below. It has 20 ticks for second number 0, etc...

EUR/USD,20161101 00:00:00.044,1.09708,1.09712
EUR/USD,20161101 00:00:00.046,1.09709,1.09712
EUR/USD,20161101 00:00:00.047,1.09708,1.09712
EUR/USD,20161101 00:00:00.053,1.09706,1.09711
EUR/USD,20161101 00:00:00.074,1.09708,1.09712
EUR/USD,20161101 00:00:00.087,1.09707,1.09712
EUR/USD,20161101 00:00:00.098,1.09708,1.09712
EUR/USD,20161101 00:00:00.109,1.09707,1.09712
EUR/USD,20161101 00:00:00.190,1.09708,1.09712
EUR/USD,20161101 00:00:00.192,1.09707,1.09712
EUR/USD,20161101 00:00:00.193,1.09706,1.09711
EUR/USD,20161101 00:00:00.340,1.09706,1.09711
EUR/USD,20161101 00:00:00.387,1.09706,1.09711
EUR/USD,20161101 00:00:00.503,1.09706,1.09711
EUR/USD,20161101 00:00:00.579,1.09705,1.0971
EUR/USD,20161101 00:00:00.692,1.09705,1.0971
EUR/USD,20161101 00:00:00.804,1.09705,1.09711
EUR/USD,20161101 00:00:00.805,1.09705,1.09709
EUR/USD,20161101 00:00:00.807,1.09704,1.09709
EUR/USD,20161101 00:00:00.871,1.09704,1.09708
EUR/USD,20161101 00:00:00.958,1.09704,1.09709
EUR/USD,20161101 00:00:01.005,1.09704,1.09708
EUR/USD,20161101 00:00:01.033,1.09704,1.09709
EUR/USD,20161101 00:00:01.147,1.09704,1.09709
EUR/USD,20161101 00:00:01.288,1.09704,1.09709
EUR/USD,20161101 00:00:01.433,1.09704,1.09709
EUR/USD,20161101 00:00:01.498,1.09704,1.09709
EUR/USD,20161101 00:00:01.773,1.09704,1.09709
EUR/USD,20161101 00:00:01.917,1.09704,1.09709
EUR/USD,20161101 00:00:01.960,1.09704,1.09709
EUR/USD,20161101 00:00:02.083,1.09704,1.09709
EUR/USD,20161101 00:00:02.214,1.09704,1.09709
EUR/USD,20161101 00:00:02.516,1.09705,1.09709
EUR/USD,20161101 00:00:02.595,1.09705,1.09709
EUR/USD,20161101 00:00:02.983,1.09705,1.09709
EUR/USD,20161101 00:00:03.330,1.09705,1.0971
EUR/USD,20161101 00:00:03.440,1.09705,1.0971
EUR/USD,20161101 00:00:03.580,1.09705,1.0971
EUR/USD,20161101 00:00:03.731,1.09705,1.0971
EUR/USD,20161101 00:00:03.787,1.09705,1.0971

I am trying to understand the nature of data - like what it actually is, where it comes from.

Yes, we can all read on the website that it is "top-of-book" Bid/Offer data. Does that data really only update a couple of times a second though?

What is precisely the nature of the Dukascopy data?

Why are there so few ticks in each second compared to the Pepperstone data?

I know that the Dukascopy platform has got some kind of a difference between "internal orders" and others - I guess that "others" means the 20+ ECN's to which it is connected?

Well, I am just guessing/grasping at straws at this stage.

Can anybody bring some good explanation to the table?

I mean, I would imagine that since the platform allows Bid/Offer and has so many users that there would be more than a couple of changes to the top-of-book in each second. Even the Pepperstone data seems a little sparse TBH.

What kind of updates would a major player such as Citadel, Jump Trading etc... be seeing in the top-of-book data? Presumably it updates for them much more frequently than 10 times a second?

Thanks in advance.