If you intend to become a resident in Portugal, advice should be taken from a local accountant.  If you do not intend to become resident, there are only two taxes that will concern you, Capital Gains Tax and Tax on rental income, should you decide to let your property out.  Your lawyer and, if necessary, your accountant, can advise you of your future liability to any of these taxes.  Note: if you are acquiring the shares of an offshore company, care should be taken as to any past Capital Gains liability that the company has accrued - 25% of gain.