That is correct, you cannot claim a tax deduction unless you...

That is correct, you cannot claim a tax deduction unless you actually sell your shares at a loss, refer to my posts prior to see the ATO link on all of this.

You will need to consider the rules regarding whether you are a trader or investor within the ATO guidelines, if you are considered an investor you have a capital loss which is only offset against capital gains and not any other income you may have.

Even if MFS is not trading which I am not sure, only reading your post and not interested in this stock, there is nothing stopping you selling them as a off market transfer to somebody to crystallise your loss...

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commentary only.... seek professional tax advice that takes your situation into account.... even though i am a professional tax adviser you cannot depend on my comments as i dont know your whole situation.....