A socio-economic analysis of the users and abusers of the tax break that is negative gearing on residential investment property casts a doubtful spotlight on the effect APRA's tightening of the vice of interest-only loans may have on a sector pursued with gusto by many lenders.Martin North, from Digital Finance Analytics, on Friday refreshed analysis on the distribution of investment property held by our core household segments, "based on marked to market values".North's data is portrayed in the chart, and elaborated below.    Limitations on the volume of new interest-only lending may, in theory, impact investors more acutely than owner-occupiers, given that around two-thirds of lending to investors is on an interest-only basis.On the other hand, the affluence and wealth of the bulk of property investors (which may parallel the affluence and wealth of the bulk of investment property borrowers) will leave sceptics wondering how much bank caution toward this critical customer segment will dampen demand.  North found "the relative value is massively skewed towards more wealthy segments," one less fazed about options and restraints around refinancing, for example, interest-only loans when needed."Exclusive Professionals, our most wealthy segment holds 27 per cent of all investment property by value, Mature Stable families hold 18 per cent, Suburban Mainstream 15 per cent and Wealthy Seniors nine per cent," the Digital Finance Analytics research found.North continued: "When we look at households by employment type, we see that employed workers hold 62 per cent by value, whilst 17 per cent are held by those not working, ten per cent by managers, nine per cent by expert professionals, and two per cent by executives."The conclusion, North wrote, is that "negative gearing is predominately used by more affluent households, and they get the biggest tax breaks as a result, which of course other tax-payers have to subsidise."