it's real obvious, too obvious actually, that generally a buyer, especially for large buyers relative to the current market action for any particular listed stock, will hold back and not place his or her real total desired number of shares to buy into the bid offer queue, or use an Iceberg order I guess (maybe)... and most especially string out all of their trades over a long period as well as break the trades into small lots if necessary as well (Phatra does this automatically with some sort of program in Bangrak for just about all live trades, no matter how big or small, as one example of this).

say there is a price gap in the queue for some time and then later some quick trades are made, bids or offers inside the gap that close out (match each other).... and someone else (not one of the buyers or traders that matched in the price gap) almost immediately enters the market for the first time at the price those trades were made at... almost as if to say "hey! I was hiding my bid.. to try to get sellers to hit a lower bid I had sitting in the queue but... hey hey... now if there are going to be any more trades at that price... now I am in too at that price.... I MUST be first in the bid queue for that" or usese some kind of automatic program (it's very fast when I have seen this) to place a bid at certain prices only if a trade closed that session at that price, but as soon as one does).

not only that, but that trader makes his or her lot size for that new bid (at the new market price) the EXACT same size lot as one or more of the in-the-gap trades were at... as if he was NOT someone who was hiding on the side but is the same trader (but not) that placed a bid or hit an offer within the gap.

My question... how many of you would guess, with a tradeable probability, assuming you know all of the above is true because you were one or both (as in self trading or managing several accounts).... that it is a back office girl with trading instructions that do not specifiy specific LIMIT prices or lots sizes but instead is something like "I want the best price of the day but more important, most of the trades on any given day must be MY bids being hit...not anyone else's".... meaning a really big buyer (bullish).... or just as likely some snook who likes to use some kind of fancy trading system that makes bids or offers only after an actual trade has closed at a particular price level or range (and therefore not so bullish at all perhaps).

is that how you would see this.... or not see anything at all?

or that you would pay attention to HOW FAST such bids or offers actually seemed to occur to guess if it is a program or a back office girl. yes? or not even try to do this kind of guessing.

always keeping in mind that except for insiders and nominees ("foreigners").... we are always only making guesses... but using it to make some money.

I find the above about as comprehensible as the following..... ;c;ksdcjnvs;dkv;Fsd;jnsd;vusVD;kvu......

I understand all the terms and I have an idea of what you are talking about, but could you rephrase your question to be more specific and direct to the point, ideally in one or two sentences?

From what I can 'guess' you are suggesting that orders are filled in a specific manner?

"I want the best price of the day but more important, most of the trades on any given day must be MY bids being hit...not anyone else's"....

I think what you are asking is, is it possible that you look at the book and always make sure the highest Bid is the one placed by yourself? This is not unusual. Especially in a thinly traded market. I.e.:

XYZ @ B=40.5 and A=41.5 (M = 41). If you look in the book and see someone trying to place a BID at 40.6 you might want to top that bid to be 40.7 (and therefore ensure you get the order filled).

This is normal market dynamics, and the more there are bidders/sellers, the closer the bid/ask gets until there is 0.01 difference or so.

Most decent trading platforms are able to execute orders like this (not a MKT order but a LMT order that gets updated as the book is updated with new quotes). Nothing unusual here and is perfectly legit.

If you are concerned about anything wrong being done in the SET you should file a complaint with the SET. The SET is an internationally recognized trading venue and could not care less if the traders are foreigners or not. (Note: People outside of Thailand can trade on SET).