if i send order to buy 1 million, the order is filled rather quickly; but when the order is 600k, even if I buy at ask, or even beyond ask price, it can not get filled staying there for whole day.
There just isn't any money to be made in small numbers in that space. Calculate how much a MM earns buying at the bid and selling at the ask on $600k and you probably have your answer. BTW, if you're at IB they have some settings you have to change to get actual bid/ask. I don't remember exactly what they are, but if you do a search here you should be able to find a discussion on it.
i used to be able to fill the ask, but after a few minute after I send order to buy at ask. even if spread is small, but ask size is still huge. i do not know why I can not lift the ask size.
Yes, u need to set Raw pricing for bonds ( if I remember correctly it doesn't t include commissions and exchange fees, in contrary to default pricing), but I can t check here what the whole process is, it s not that straightforward to find out the setting. Also FWIW while sending 7digits buy orders on the ask with Raw settings on it might still take a little while to get filled ime
this account had no problem buying t-bill a few months ago. in another linked account, i already bought 1 million t-bills. but this account 600k can not get filled for a few days.
i got filled 500k after setting raw price. it is in tws/global configuration/display/ticker row/fixed income pricing.