Welcome to NexusFi: the best trading community on the planet, with over 150,000 members Sign Up Now for Free
Genuine reviews from real traders, not fake reviews from stealth vendors
Quality education from leading professional traders
We are a friendly, helpful, and positive community
We do not tolerate rude behavior, trolling, or vendors advertising in posts
We are here to help, just let us know what you need
You'll need to register in order to view the content of the threads and start contributing to our community. It's free for basic access, or support us by becoming an Elite Member -- see if you qualify for a discount below.
-- Big Mike, Site Administrator
(If you already have an account, login at the top of the page)
Tape/Time and Sales: why actual trades do not decrease bid/ask sizes?
I have received an answer from DTN IQFeed about EUREX feed. As always with them, quick and very precise.
DTN IQFeed send to their clients exactly the data they receive from EUREX, with no filtering or altering.
DTN IQFeed have checked in the feed, and they have observed the same behaviour as the one I underlined above (with the colors).
For instance (this is my example, not theirs):
[108761] Update without trade: Ask = 458 @ 2484.00 - Bid = 270 @ 2483.00 | 2012-08-21 02:42:29
[108762] New trade at the BID: 10 @ 2483.00 - Ask = 458 @ 2484.00 - Bid = 270 @ 2483.00 | 2012-08-21 02:42:29
[108764] Update without trade: Ask = 487 @ 2484.00 - Bid = 216 @ 2483.00 | 2012-08-21 02:42:29
--> 270 - 10 is not equal to 216.
DTN IQFeed have even sent me a snapshot of the EUREX T&S data they see with a similar example, to confirm that they observe the same phenomenon.
So, at this stage, my preliminary conclusion is that this "issue" is not due to my coding or to DTN IQFeed, but to the way EUREX send their Level 1 T&S messages.
Reminder... I expected that: Bid size shown in next "quote update" message after a trade at the bid = bid size before the trade minus size of the trade
It is the case for CME.
It is not the case for EUREX.
Below please find their explanation.
In short, and as far as I understand, the "quote update" messages are not a continuous feed reflecting all updates of inside bid / inside ask. It is more a "snapshot" sent regularly.
So, between the trade and the next "quote update" message, inside bid/inside ask might have already undergone several actual updates.
