Past performance is no guarantee of future returns … this well-known warning – printed regularly on all investment prospectuses, and rightly so – demonstrates quite simply how much financiers tend to focus on the future and on what tomorrow might bring rather than dwelling on the past. But looking ahead does not mean ignoring yesterday's lessons. Although no two financial shocks are ever the same, they often display strikingly similar patterns: when speculative bubbles – whether in tulips in 1637, railways in 1845 or the Internet in 2000 – burst, it is always sudden, investors change their minds without warning and, with the crisis at its height, markets simply grind to a standstill. The risks facing investors are legion, but no matter how much they remember these past mishaps, there is no way of predicting the exact timing or repercussions of tomorrow's shocks. In this respect, knowledge of the past is useful, but by no means vital.

There is, however, another part of the financial universe that evolves less erratically, tracking a more predictable course: the business of settling transactions, transferring deposits and assets, trading securities, organising the structure and legal status of the main intermediaries – a complex set of functions encompassing most back-office banking operations and the hidden cogs of the financial sector's machinery. Highly intensive in physical and human capital, structures of this sort are always slow to change.