The legislation that governs this topic has recently changed, but neither the old legislation nor the new legislation delineates what types of investments (other than developed real estate and cash) are acceptable for this category. This means that your safest bet (depending on which of the four categories of PR by independent means you are aiming for) is to deposit the requisite amount of money in an account here and/or invest the requisite dollar value in developed real estate. Note that you always have the option to write to the immigration department and ask if an alternate investment type is permissible in your circumstances.
