Private investor the Kador Group has bet on a re-rating of the Pyrmont office market, buying a heritage-converted office complex in an off-market deal for just over $80 million from Anton Capital.

The deal reflected a sub-6 per cent yield, which is a record for Pyrmont, property sources said. The area has an ultra-low office vacancy rate and is set to benefit from new infrastructure such as the new Convention and Exhibition Centre and Mirvac's redevelopment of Harbourside Shopping Centre.