By Yantoultra Ngui

SINGAPORE (Reuters) - Singapore's biggest bank DBS Group posted on Thursday a record net profit in the third quarter, but forecast 2025 net profit to be below 2024 levels because the city-state is introducing a global minimum corporate tax rate.

DBS, the first Singapore lender to report third-quarter results, said July-September net profit surged 15% to S$3.03 billion ($2.27 billion), easily beating the mean estimate of nearly S$2.80 billion from five analysts, according to LSEG data.

It also topped the previous quarterly record of S$2.96 billion it set in the first quarter this year, even though its net interest margin, a key profitability gauge, declined to 2.11% during the third quarter from 2.19% the same quarter a year earlier.

The strong result came on the back of record fee income driven by wealth management, higher treasury customer sales and increased markets trading income.

Singapore banks have benefited from higher global interest rates and strong inflows of wealth drawn in by the city-state's political stability in recent years.

But rate cuts by big central banks and volatile markets due to global geopolitical and economic uncertainties are set to weigh on their growth momentum, analysts have said.

DBS forecast 2025 pre-tax profit and group net interest income to be around 2024 levels, according to CEO Piyush Gupta's observation slides accompanying the results. But net profit after tax will be lower next year due to a 15% global minimum corporate tax being introduced by Singapore from January and imposed on multinational companies including DBS.

DBS, which is also Southeast Asia's biggest bank, announced quarterly dividend of 54 Singapore cents per share, up from 48 cents declared the same quarter a year ago.

The bank also announced that its board had established a new share buyback programme of S$3 billion.

"The new buyback programme we announced today is underpinned by our strong capital position and ongoing earnings generation, and it is another affirmation of our commitment to capital management," Gupta said.

Jefferies equity analysts Sam Wong and Shujin Chen said in a research note following the results that they expected a positive share price reaction.

"This is a very strong set with results, with positive surprise in capital return," they said in the note. Local rivals Oversea-Chinese Banking Corporation and United Overseas Bank are scheduled to report their quarterly results on Friday.

($1 = 1.3324 Singapore dollars) (This story has been refiled to add the missing name of the bank 'DBS' in paragraph 8)