貨幣とビットコインに対する課税についてのメモ

お金に縁がないので、電子マネーにせよ、ビットコインにせよ、興味がなかったのであるが、ちょっと面白い記事。

Bitcoin vs Electronic Money | CGAP

　電子マネーというのは、基本的に普通の通貨の運用と並行的にリンクされているわけですね。ところが、ビットコインは、

At its core, Bitcoin is nothing more than a digital file that lists every transaction that has ever happened in the network in its version of a general ledger called the “block chain.” Bitcoin is the first example of a growing category of money known as cryptocurrency in which open-source software solves complex mathematical calculations to mine more Bitcoins (Coin Desk 2013a). These “miners” make the Bitcoin network function by validating transactions and thereby creating new Bitcoins. This occurs when the Bitcoin network collects all the transactions made during a set period of time (usually every 10 minutes) into a list called a “block.” Miners confirm these blocks of transactions and write them into the block chain by competing against each other to solve mathematical calculations. Every time a miner’s system finds a solution that validates a block of transactions, that miner is awarded 25 Bitcoins (Coin Desk 2013b). Every four years, this reward is halved so that the total number of Bitcoins will never exceed 21 million.

ビットコインは最大発掘量が制限された電子コインで、取引がすべて元帳に記載されるデジタルファイルである、と。


で、貨幣、つまり、マネーとは、ものやサービスの交換の媒体であり、後にいろいろなものやサービスに化ける価値の保蔵機能を備えており、ものやサービスを数量で表すことができる尺度機能を備えている、といわれている。

　ビットコインの場合、

Why Bitcoin Can No Longer Work as a Virtual Currency, in 1 Paragraph
A single bitcoin no longer functions like a $20 bill.
ROBINSON MEYERMAR 26 2014, 12:49 PM ET

As a store of value, Bitcoin’s price had to be predictably stable, such that you could neglect to spend a single bitcoin and know its value would not fluctuate wildly. In late 2013, many argued that Bitcoin’s quickly rising price kept it from functioning as a dependable store of value, but there were no technical or regulatory reasons it couldn’t function as such eventually.

As a medium of exchange, Bitcoin must be commonly desired. People must want to have Bitcoin; others must want to spend it. (Thus, it avoids the ‘coincidence of wants’ problem―in order to trade, both people don’t need to want something the other person has. Instead of trading rent for food, for example, you can rent living space from a landlord with money, and your landlord can use that money to buy food.)

Finally, as a unit of account, Bitcoin had to have a standard numerical value to be used to measure profits and settle debts. It had to be divisible (which it was, since smaller units of bitcoin could be traded); it had to be verifiable (which it was―this formed the basis of its cryptosecurity), and finally, it had to be fungible, meaning that every bitcoin was the same as every other bitcoin.

　価格が乱高下して、価値の安定した保蔵機能は少ないとも言われたが、しかし、原理的には価値の保蔵機能があり、交換の媒介として、流通し始め、また、分割、証明可能であったから、通貨としての有力候補であったが、この度、アメリカ合衆国内国歳入庁がビットコインを通貨ではなく、資産として扱い、税金の対象となる、としたことで、代替可能性がなくなり、通貨としては機能しなくなった、と。

　売却益に税金がかかってくる、ということは、

　

The price at which a particular Bitcoin was acquired (and this is traceable) determines the capital gains on that particular Bitcoin when spent. If I spend Bitcoin A, which I bought at $10, but is now worth $400, I’ve got a very different tax treatment than if I spend Bitcoin B, which I bought at $390. […] This means Bitcoins are not fungible, and that makes it unworkable as a currency.

　仮に現在、一ビットコイン４００ドルとして、１０ドルで買ったビットコインAを使うのと、３９０ドルで買ったビットコインBを使うのでは、税金のかかり方が異なり、ATMの一ドルを財布の中の一ドルと交換可能のようには、一ビットコインが他の一ビットコインと代替可能ではなくなり、

If I have to figure out which particular Bitcoin in my wallet I want to spend and what the tax treatment will be, Bitcoin just doesn't work as a commercial medium of exchange.

どの一ビットコインを使うか、悩まなくてはいけないようでは、交換の媒体にもならん、と。

もっとも、投機の対象にはなる、と。