You can't say much beyond a snappy title in 140 characters, so I thought I should write a short post explaining what I meant.
You can, if you want, think of (central bank) money as shares in a closed-end mutual fund. The mutual fund has assets, that are mostly financial assets. The returns from those assets can be used either to pay "management expenses" or else are given to the shareholders in the form of dividends or share buybacks. Unlike open-end mutual funds, the shares can be traded, but you don't have the right to redeem them for a percentage of the underlying assets. You don't have the right to redeem them at all.
Commercial bank money is redeemable at a fixed exchange rate for central bank money. (I call them "beta banks", because this means they follow the "alpha" central bank's lead in setting the value of their money.)
Currency does not usually pay dividends (either positive or negative) for the simple reason that it is administratively difficult to do so. But the capital gains from share buybacks (or capital losses from dilution) are an alternative to paying dividends (negative dividends), so that problem with the metaphor shouldn't matter much.
Currency is used as a medium of account (we measure prices of other goods in terms of the closed-end mutual fund shares), which makes a difference if prices are sticky.
Currency is used as a medium of exchange (we can buy and sell all other goods with the closed-end mutual fund shares). This makes a difference, because people will hold a medium of exchange even if the expected rate of return is very negative (Zimbabwe), even though they won't hold as much. (Demand curves slope down).
And central banks can decide on any "management expense ratio" they feel like, diluting the shares by printing loads more shares, and giving the profits to the government which owns the mutual fund.
So, like all metaphors, it works and it doesn't work. It works better in some places than in others.
The metaphor seems to work rather well for Switzerland.
First because the Swiss seem to want the Swiss National Bank to target very low inflation. This means they want a low management expense ratio.
Second, because there seems to be a big demand for Swiss Francs from outside Switzerland, where people do not care about Swiss Francs being used as a medium of account and medium of exchange within Switzerland.
And, unless the Swiss impose exchange controls (which they don't want to do), this means the Swiss National Bank must satisfy that demand for Swiss Francs, because if it fails to issue enough Swiss Francs to satisfy that demand, the fact that the Swiss Franc is used as medium of account and medium of exchange within Switzerland will screw up the Swiss economy. Because an excess demand for money causes a recession.
So, given the circumstances, the Swiss National Bank has no choice but to see itself as operating a closed-end mutual fund where it must do everything it can to ensure that shares in that mutual fund do not appreciate too much, and the only way it can do that is by making its mutual fund as large as it needs to be. And since the Swiss National Bank is owned by Switzerland, and it is Switzerland as a whole that both gets the profits from operating the mutual fund and covers any possible losses, we can say that Switzerland as a whole is one big closed-end mutual fund. And the Swiss commercial banks, which operate open-end mutual funds whose shares are redeemable at a fixed exchange rate for those closed-end shares, are just part of the same story.
Andy Harless put it succinctly, in replying to my tweet: "Switzerland should just buy everything in sight".
And enjoy the fruits of a small "management expense ratio" multiplied by a very large mutual fund.
Switzerland is not Iceland. Shares in a closed-end fund may fall in value, but the fund cannot default. Iceland was a beta bank with a country attached.
[How do I link to a tweet?]