1. A computer-implemented method of calculating an index value comprising: determining a fixed base value of a breakout index; receiving an indication whether an entity of a monetary union issues a first breakout currency; and wherein if the first breakout currency is not issued, calculating with a processor an initial index value of a prospective breakout index based upon a prospective breakout currency, the calculating comprising: receiving an index value of an index based upon a currency of the monetary union; combining the fixed base value of the breakout index with the index value based upon a currency of the monetary union to calculate the initial index value of the prospective breakout index; wherein if the first breakout currency is issued, upon its issuance, calculating with a processor an initial index value of a breakout index based upon the first breakout currency, the calculating comprising: receiving an initial exchange rate of the first breakout currency against a currency of the monetary union; determining a breakout value of the first breakout currency, wherein the breakout value is established as a reciprocal of the initial exchange rate; and combining the fixed base value of the breakout index such that the initial index value of the breakout index is equal to the fixed base value; and receiving bids for a breakout financial instrument based upon at least one of the breakout index or the prospective breakout index.