By Ben Otto

Hang Seng Bank Ltd. said its net profit for the first half fell 33% as Hong Kong wrestled with weaker economic activity amid the Covid-19 pandemic, trade tensions and social unrest.

Net profit for the period was 9.14 billion Hong Kong dollars (US$1.18 billion), compared with HK$13.66 billion a year earlier, the Hong Kong-based lender said in a stock-exchange filing Monday.

Results were affected by factors including lower net interest income, an increase in expected credit losses and a net deficit on property revaluation, Hang Seng said. The bank booked HK$1.76 billion in expected credit losses and other credit impairments, up from HK$510 million in the same period a year earlier.

Net interest income fell 6.7% to HK$14.79 billion in a lower interest rate environment, while noninterest income dropped 33% to HK$4.40 billion, the bank said.

Hang Seng said it expects the pandemic, geopolitical tensions and other uncertainties to continue to disrupt industrial and commercial activity, reducing consumer spending and investor appetite.

Write to Ben Otto at ben.otto@wsj.com