AustralianSuper, the country’s largest superannuation fund, has been forced to write off more than $1.1 billion in equity and loans tied to an American online education start-up, marking it as its single worst investment in venture capital.

The fund, which manages $341 billion in retirement savings for more than 3 million people, has aggressively expanded its investments in private credit and private equity, including in the United States. But it has worn a loss of $US757 million on Pluralsight, a Utah-based video training firm once valued at more than $US5 billion.