AIB has begun writing to business customers with balances in excess of €1m to inform them that it intends to increase the negative rate they will be charged on their deposits to -0.75%.
The change will take effect from the end of March and will see the negative rate increased from the current -0.5% they are currently charged.
The move comes as banks wait to see if there is some kind of change in European Central Bank policy on rates in order to tackle rising inflation.
For the past 8 years, the ECB has been charging banks who deposit money with it negative interest rates in order to encourage them to increase lending and their customers to increase spending.
"AIB has insulated the vast majority of our customers during a sustained period of European negative interest rates," the bank said in a statement.
"The huge growth in customer balances, especially during the pandemic, has increased the cost to the bank of providing current and deposit product services, including negative interest rate costs."
"As a result the bank has continued to keep its negative interest strategy under constant review."
Around 3,000 corporate customers will be impacted by the move to increase the charge for holding balances over €1m.
The bank had signalled last year that it would also begin applying negative rates to personal customers with balances over €1m by the end of 2021.
It has now begun writing to those personal customers to let them know this will not now begin until May.
Around 1,700 personal customers are likely to be hit by the decision, up from around 100 who currently have balances over €3m which are the subject of negative rates.
Other Irish lenders, including Bank of Ireland and Ulster Bank, also apply negative rates to customers with balances over €1m.