The Regulatory Authority of Qatar Financial Center (QFC) said on Sunday it was prohibiting First Abu Dhabi Bank (FAB) from undertaking any new business for customers of its Doha branch.
It has barred FAB from providing services for new customers since March but had allowed the bank to continue working with existing customers.
QFC said in March that FAB had failed to produce documents relevant to the currency manipulation investigation.
In a statement on Sunday, QFC said the new bar was "because FAB continues to fail to satisfy the Regulatory Authority of its fitness and propriety in respect of its conduct in the QFC".
Since 2017, the UAE along with Saudi Arabia and its allies have enforced a boycott of Qatar including bans on shipping, trade, direct flights, overflight and land crossings.