I went to my local TMB local branch to make a the 1st time a test teller counter withdrawal using my US debit card. I had previously gotten approval to extend my withdrawal limit from my US bank. Based on 28B/US dollar I would have been able to withdraw 112,000B but I request 100,000B to be on the conservative side. The bank rep called Bangkok to confirm the amount, but was told, I could not withdraw that amount. To minimize an hassle (I speak very little Thai and she, very little English) I lowered the amount to 80,000B which Bangkok accepted.

My question to those WHO KNOW, no guesses please, Even though, I was approved by my US bank to withdraw $4000, do the THai banks cap the withdrawal request at a lower percentage of the request?

Please note, soon after, I went to the Aeon ATM at Airport Plaza and was able to withdraw an additional 30,000B + 2000B which with the 80,000B would have been close to the $4000 my bank approved. Both the withdrawal exchange rate from the Thai bank and ATM were practically identical at 28.71B. I used my schwab debit card.

Thanks for you informative comments.

Color me stupid, but I never knew you could use a U.S. debit card to take cash at the teller window. Learn something everyday! Do you swipe your card & enter your PIN? And do you pay the same 150 THB fee you would pay at the ATM?

Sorry, I can't answer your questions. Probably nobody can.

Sure, I expect the local bank you are doing the transaction at can limit the amount of a transaction to protect themselves/comply with their own policies regardless of what your home country bank debit card may authorized per day. Some branches won't do a foreign debit card withdrawal at the counter...they will tell you to go over to the ATM and do it. Kinda like the max you can get from an ATM regardless of what your ATM/debit card authorizes...some Thai ATMs limit each withdrawal transaction to 25K baht...some 30K baht...some 40K baht. But if you debit card had an unlimited daily withdrawal amount you could just slide you card into the ATM and pull another 25K...30K...40K...etc.

withdrew 200,000 baht at the counter using my UK barclays bank debit card this is about $6000, i guess the limit is determined by the bank at home

The Thai bank that you used set the lower limit to protect themselves. Once they get to know and trust you, they will raise the limit to match your U.S. bank.

We have been discussing the use of U.S. bank debit cards to withdraw cash at Thai bank teller windows for several weeks now on this forum: http://www.thaivisa.com/forum/topic/632460-bangkok-bank-again/