Why? Diversification is the key to removing volatility from an investment portfolio and having all your eggs in one basket is opening yourself up to more risk.
Investopedia defines diversification as "A risk management technique that mixes a wide variety of investments within a portfolio. The rationale behind this technique contends that a portfolio constructed of different kinds of investments will, on average, yield higher returns and pose a lower risk than any individual investment found within the portfolio."
The 2017 Russell Long Term Investment Report lists Australian residential property and Australian shares as the top two for averaged returns over the past 20 year year period. Both asset classes have done well over the long term and both are good growth classes.
The Russell report shows that Australian property has done especially well over the past few years due to the low interest rate climate. Borrowing for residential property investment has been relatively easy and households have been able to take on more debt. However, if interest rates climb over the coming economic period then the great growth in residential property values that we have been experiencing will dry up very quickly.
Australian shares may be due for a resurgence, especially if the economy picks up and investors start to shift their sights away from property. Australian shares also provide the benefit of franking credits, where company tax paid is passed on through to Australian investors, provided a tax-efficient boost to earnings.
Don't stop at Australian shares either. The ASX represents around 2% of the global economy so picking up some international shares via an exchange-traded fund (ETF) will also diversify your share portfolio significantly.
So if you have the option to invest in both Australian property and shares then do it. If you only have property then be sure to consider diversifying to shares. More diversification in your portfolio is a good thing since it will help reduce the volatility of returns.