> A stock can only have a single holder of record, and only one dividend payment should ever be made to whoever the holder of the stock was at the time of the p

> A stock can only have a single holder of record, and only one dividend payment should ever be made to whoever the holder of the stock was at the time of the payment. Yes you are right with this. I have suggested a way to handle this to my colleagues informally, but I don't work with the tax offices themselves. What I would do is to have each share at the atomic level as you mention to have a serial number. If you reclaim for 100 shares then you need to supply 100 serial numbers. With regards to the banks, absolutely, they are the critical step in this kind of fraud. The serial number solution does have one weak point: You can use "unused" serial numbers for your reclaim or you can use serial numbers from someone who lives in a country that does not participate in the bilateral treaty that allows the reclaim. This latter example is also essentially using "unused" serial numbers. Typically there are many billions of dollars of withholding tax that remains unclaimed for whatever reason, sometimes even just ignorance. But at the very least this allows you to be better off than today. The tax offices, if they are competent, can even try to attach each serial number to a person, but there are privacy laws that can prevent this. Another subtle point is that a dividend payment event is not the same thing as receipt of the dividend in your account. Typically, the receipt of the dividend is the critical point that tax offices want, not proving ownership of the dividend. This is why the banks have so much power here. They essentially prove payment receipt, not dividend ownership. The logic is that you can't have had the payment into your account if you didn't have ownership of the dividend. There are also other examples of fraud such as forging the country of residence of the shareholder. Oh yes, and then lastly: Apparently around 2009 some countries turned a blind eye to cum-ex because they saw it as a way to "boost the recovering economy" by pushing up bank revenues... ¯\_(ツ)_/¯