Pressure is again mounting on the Swedish pension group embroiled in the Silicon Valley Bank fallout this spring after prosecutors opened an investigation linked to the fund’s single largest investment.

Stockholm-based Alecta was last week referred to the public prosecution authority by the country’s financial watchdog over a $4.6 billion stake in commercial landlord Heimstaden Bostad AB, according to comments by the Chairman Jan-Olof Jacke.

“I have initiated a preliminary investigation due to the report filed by the FSA concerning Alecta,” Johan Lindmark, a prosecutor at the National Anti-Corruption Unit, said by phone. He added he doesn’t expect to make a further announcement before the end of December.

The development comes after Alecta submitted the findings of two separate legal opinions to the country’s Financial Supervisory Authority. Its internal probes, which began in September, centered on whether the pension fund had correctly followed the rules in building up a 38% stake in one of Europe’s biggest residential real estate firms.

Sweden’s biggest private pension fund has remained in the spotlight ever since it lost $2 billion on three failed bets tied to the US banking crisis earlier this year. That debacle led to the ousting of Alecta’s Chief Executive Officer Magnus Billing and equities chief Liselott Ledin. The group’s chief investment officer, Henrik Gade Jepsen, also stepped down in the summer while its chairman, Ingrid Bonde, quit last month.

Now the pressure is once again ratcheting up after its investment in one of the largest landlords in Europe began souring amid a widespread funding crunch in Sweden’s property sector, where borrowers such as Heimstaden Bostad are struggling to refinance billions of dollars of debt amassed in the cheap-money era. The pension fund has already written down the value of its investment amid the crisis.

“If a corruption crime has been committed, this could have a clearly negative impact on Alecta’s possibilities to support Heimstaden Bostad,” Danske Bank credit analyst Marcus Gustavsson said in a note to clients last week.