Around two thirds of all KiwiSaver money is invested via a bank.
The two largest providers in New Zealand - ANZ and ASB collectively oversee just over 44 per cent of KiwiSaver members assets under management and the market share held by banks is growing.
But should you switch your KiwiSaver money to your bank?
For many people having their KiwiSaver account with the same business that has their mortgage, savings and credit cards seems like an easy solution.
Like checking a bank account they can look at their balance online on their phone or computer.
But financial commentator Mary Holm says the ability to check your KiwiSaver account frequently is not a good reason to move providers.
"In recent times with markets going up to go to your balance and see it doing well has made people feel good."
But the opposite may be the case now that markets are falling.
Holm recommends people do not check their balances more than once every three months.
"Quarterly is plenty."
Holm said people who get approached to switch KiwiSaver providers should go to the sorted website and check out the fund finder tool.
The tool asks questions to find out which fund is appropriate for you and then ranks the funds in their categories based on fees, services and returns.
Holm said savers should pay more attention to fees and services which are likely to remain consistent and avoid picking a fund based on past returns as past performance can not predict how it will perform in the future.
Paul Gregory, director of investor capability at the Financial Markets Authority, said banks had an obligation to talk about their KiwiSaver scheme in a way that was accurate and balanced and should put their customer's interest first.
"They can't just talk about the benefits."
Gregory said savers should use the approach as a prompt to look at why they are in KiwiSaver and figure out how much they will need by retirement age.
While a KiwiSaver provider may promote their fund as being a top performer Gregory said it may be that an individual doesn't need to take on the risks linked to that performance to save for the kind of retirement they want.
It all has to be seen through the purpose of what you are saving for.
Gregory said for some people that may not be an easy question to answer and that may be something the bank can help them with.
For personalised advice people need to see an authorised financial adviser many of which do work for the banks.
Gregory said people should not be afraid to ask tough questions like; do you get any benefit from me switching to this scheme?
"If you are being put under pressure, that is probably a good indication you shouldn't act quickly."
The FMA has a guide on getting KiwiSaver advice.
Binu Paul, principal of SavvyKiwi - an independent KiwiSaver research company, believes the biggest mistake people can make is just to sign on the dotted line.
Paul said people approached by their bank to switch their KiwiSaver business should ask for three reasons why they should switch and then ask the bank to back up those reasons with evidence.
"If they say they have the top performing fund in the last five years ask them to prove that. Make the person work for the business."
Paul said savers should remember that front-line bank staff may get paid based on the number of sales they make.