This was an increase of €1bn, or 5pc, since March last year.
Deposits rose by €300m from the end of December alone, according to the bank, which is still majority owned by the state.
The bank’s market share of mortgage drawdowns in the first three months of the year was 13.4pc, down from 15.4pc in the final quarter of 2023.
This followed a slowdown in switching activity in the quarter following a similar pattern in the second half of 2023.
In an interim management statement PTSB said it had “overperformed” in the switcher market during the first half of 2023 and pointed to intense competition for first-time buyers at present. About 73pc of new mortgage drawdowns were linked to fixed-rate products.
The bank also saw its net interest income, the key driver of bank profitability, rise 10pc in the first three months of this year compared to the same period in 2023.
PTSB’s net interest margin, the difference between the interest a bank charges borrowers and how much it pays savers, also rose five basis points to 2.31pc in the same period. Gross interest income was also up 37pc year-on-year.
The bank attributed this growth to higher interest rates, as well as an increase in average interest earning assets. However, this was partly offset by a higher cost of funds as a result of a rise in deposit volumes in recent months.
Total operating income was €167m in the first quarter, up 9pc from the corresponding period in 2023.
Operating expenses remained in line with expectations, according to the bank.
The bank also reported that business banking lending had grown to €80m in the first quarter following the acquisition of Ulster Bank’s Lombard asset finance business.
Net loans and advances to customers rose 7.5pc year-on-year to €21.3bn. This dipped 1pc over the quarter as a result of a slowdown in new lending, as well as contractual payments and redemptions.
Overall, the total performing loan book at PTSB stood at €20.8bn, 1pc lower than last December. Non-performing loans were around €700m at the end of March, in line with what was reported at the end of December.
PTSB said its guidance for the full year remained in line with prior expectations.
Earlier this year, following the publication of the bank’s 2023 annual results, PTSB said it expected net interest income to be broadly in line with last year’s figures.
“PTSB recorded a strong financial performance in respect of key financial metrics in Q1, including an increase in net interest income (+10pc), net interest margin (up 5bps) as well as a doubling of business lending,” chief executive Eamonn Crowley said. “Our mortgage market share during Q1 declined slightly from Q4 2023 and continues to be impacted by the reduced switcher market.”
Mr Crowley also pointed to the bank’s move into the retrofitting market as it became the first lender here to offer the Government-backed Home Energy Upgrade Loan scheme.
In a note to investors Davy analyst Diarmaid Sheridan said: “While net lending is modestly lower, the roll-out of new products and changes to the existing line-up should support recovery from here and should also be seen in the context of a 40pc increase in customer lending since Q3 2022.”