Some more reading material for those that are keen on minimizing costs(or just curious):
This discussion could probably go in a new thread?
Both are in japanese but I'll try and summarize the first(which just feels like a better overview):
Discussion of foreign ETFs vs low-cost domestic funds:
http://shintaro-money.com/kaigai-etf-relay/
This seems to be a much more complete and accurate treatment of taxation than the other article. In particular of interest is the three layered taxation on VT or similar US-domiciled ETF's: first, the dividends inside the etf are taxed by the local country(except the US). Then the dividends put out of the ETF are taxed by the US. Finally, japan takes its cut of 20%. In practice with the US compromising ~half of vt, and not taxing both sides of the domestic stuff, that amounts to ~14.5% before japanese tax(so that is taken whether in nisa or not). Of that, you can apply for a tax rebate up to 10%, but apparently you're not guarrenteed to get it all. The article works with getting back 5%. So effectively the taxes you pay on the dividends outside nisa are 9.5% then 20.5% or inside nisa, 9.5%.
Against that you're dealing with an index fund, which has higher costs(~.28% real costs for tawara vs .1% for VT), gets taxed once inside(for each stock in the country of origin) and once outside(for japan). You can't get any rebate on the stuff inside so it's going to be ~10% off dividends. The remainder goes back into the fund and is counted towards capital gains taxed at ~20%(or 0 for nisa), so it's still getting double taxed, but it compounds on only the first(foreign dividends) tax.
What does that all mean? The take-home is that without nisa you're looking at more or less equal outcomes(ignoring trading/exchange costs on the etf) on one-year if you get that 5% tax rebate. In a NISA account you get slightly better returns on the ETF.
This treatment however doesn't cover reinvesting the dividends and compounding over the long term. It would be an interesting exercise to check for a rainy day.
Either way:
The short-term difference between straight up investing in VT or investing in a quality low-cost domestic world index seems to be pretty small. So long as you get that tax rebate. Inside a nisa I suspect that though the VT does better in the short term, because the fund "expands" your tax-free slot that a low cost fund would do better.
This particular blog really digs into the differences and also discusses the issues of domestic funds that hold etf's:
http://tawaraotoko.blog.fc2.com/blog-entry-652.html
It's worth noting that although on paper exe-i has lower costs than say tawara and nissei, that exe-i is holding etfs and in turn getting that triple-tax whammy so it is questionable whether they can outperform the funds that hold stocks and on paper have higher management costs.
What is interesting to me is how deceiving those base cost numbers can be. In the end of the day the visible costs will go(lowest to highest) foreign etf < etf-backed fund << pure fund while the hidden tax costs will go the opposite direction. What actually wins out in practice is a complex function of length of holding, the proportion of dividends to capital gains, and how much you actually get back on your foreign dividends tax return.
edit: I updated the spread-sheet I made to take in this new info:
https://docs.google.com/spreadsheets/d/ ... sp=sharing
It's a work in progress but I think it's accurate. I'm changing the comparison from VT vs VT-rakuten because I think rakuten-vt will always lose to VT: despite being an etf-backed fund, it costs the same as a pure funds while eating most of the tax issues of the ETF. I'm going to use the 0.28% costs of the "pure fund" tawara from the shintaro article.
The spread sheet is for taxable accounts only! If I get some more spare time I'll try to do the same thing for nisa. At this time using the figures from shintaro's blog and assuming a 5% foreign dividend tax rebate on the VT, the results are absurdly close(less than 1% after 20 years). Interestingly enough the advantage grows to a .72% peak at 23 years and then it starts shrinking as the power of the lower taxed dividends compounding has the fund catching up, with the gap down to .1% after 40 years. Without the foreign tax rebate it's a straight loss for vt