The Dunedin City Council's investment fund is doing particularly well, thanks to favourable exchange rates and returns on equity.

The Waipori Fund's net operating result was just over $4.5m for the first six months of the financial year.

That's about $3m more than budgeted.

A large chunk has come from exchange rate gains, through investments held in foreign currency.

And more than $2m has been gained through equities.

The council also had a relatively large operating surplus in the last half of 2014.