What is the duration for which an investment will be considered a long term investment in mutual funds, shares etc?
The question is vague but I will assume that you want to know how to differentiate between long-term/ short-term investments in relation to Zakat.
There is no technical definition of any of them from a shariah perspective.
However, to help people understand, we use these terms to differentiate between the 2 different types of assets classes i.e. those that are bought to generate an income (which in general are bought for a long- term period) and those bought for the purpose of capital growth (which in general are bought for a shorter-term period).
Otherwise the principles behind the Zakat calculation is that: – the value of anything bought for the purpose of resell or capital growth is subject to Zakat. This is in contrast with: – an asset which has been bought for the purpose of generating an income only. The value of such asset will not be Zakatable.