COPENHAGEN, Feb 28 (Reuters) - Alecta, Sweden's largest pension fund provider, said on Wednesday its holding in property group Heimstaden Bostad lost 25% of its value in 2023, corresponding to a 12.7 billion Swedish crowns ($1.23 billion) hit.

Heimstaden, a real estate group with swathes of homes from Stockholm to Berlin, on Tuesday said it had written down the value of its investment properties by 31 billion crowns, plunging it to a pre-tax loss in 2023 of 29 billion crowns.

The Swedish real estate sector is under pressure as many companies grapple with large debts, rising interest rates and a wilting wider economy.

Alecta owns a 39.4% stake in Heimstaden Bostad. ($1 = 10.3433 Swedish crowns) (Reporting by Louise Breusch Rasmussen, editing by Terje Solsvik)