Even with the sound on, you never hear television pundits talking about asset-turn. That is a shame because the ratio is key to understanding these annoyingly indecisive bond and equity markets. To be fair, it is not a widely known term. Worse, it could mean anything and is written inversely to how it is calculated (revenues divided by assets). Asset-turn is also hard to conceptualise.

Finance students may remember it as one of the three ratios the DuPont Corporation began multiplying together in the 1920s to derive return on equity (RoE) — the other two being leverage and net margin. While most people more or less get profitability and debt, the sales a company generates from its assets is less intuitive. Quickly now: is 0.9 or 0.6 the better number?

The reason the answer has not mattered much is that margin growth has been the primary driver of RoE and stock markets over the past 20 years. So successfully has profitability boosted returns that investors are most ignorant of the long-run decline in asset-turn. From a dollar of S&P 500 assets supporting one dollar of revenues in 1995, for example, half the turnover is made today.