Why is my Kiwisaver going down? Bank economists say Kiwisaver balance dropping is completely normal

New Zealand bank economists say a decline in Kiwisaver balances over the past week is fairly normal and nothing to worry about in the scheme of things.

Declines of somewhere in the region of five per cent have been seen by some Kiwisaver account holders over the past week as international growth-type stocks and investments dropped.

The US stock market plunged more than 600 points yesterday, NZT, but has rebounded somewhat today.

ASB Chief Economist Nick Tuffley said such drops and rises are normal, and can be caused by a range of international factors, from political issues to complete speculation.

"For people who are looking frequently at their Kiwisaver balances at the moment, amidst the weaker sharemarkets that we've had globally - that's when people with some exposure to equities would have noticed some drop in the value of their portfolios," Mr Tuffley said.

"Any Kiwisaver portfolios who have an exposure to either international equities or Australasian equities would have picked up some degree of fall in prices.

"If you do look at it every day, you're always going to see a degree of volatility.

"What we've got to remember is that it's a long-term retirement savings product, so we shouldn't get too worried about ups and downs from one day to the next, because the focus is on where we're going to be in the future over the longer term."

ANZ Chief Investment Officer Paul Huxford said the range of factors influencing investment fund performance is wide.

"The speed of rate increases in the US, the escalation of this tarrif piece between the US and China, we've seen issues in Italy around their budget, we're leading up to [US] mid-term elections, the Saudi piece and whether that escalates, and we've got high oil prices at the moment," Mr Huxford said.

He said overall, 2018 has been a very strong year for Kiwisaver funds, and people should bear that in mind, adding that Kiwisaver account holders should take steps to educate themselves on their Kiwisaver investment in order to choose the right portfolio for their age.