The International Monetary Fund delivered a valuable imprimatur of respectability to Beijing last week, when it declared that its exchange rate was probably no longer undervalued. The assessment was not a surprise: respected independent outfits such as the Peterson Institute and the consultancy Oxford Economics have been saying similar for a while.

The judgment increases the already rising probability that the renminbi might be included in the units that make up Special Drawing Rights (SDR), commonly though inaccurately known as the IMF’s currency, when the composition of the basket is reassessed later this year. Some regard this as a pivotal moment in the internationalisation of the renminbi. But history suggests that, while it may be symbolically important, membership of the SDR is neither necessary nor sufficient for the renminbi’s acceptance as a global reserve currency.

The SDR asset, sometimes likened to a monetary Esperanto, is a peculiar creature. Created in the 1960s to meet the world’s demand for reserve assets when the dollar — constrained by its link to gold — could not do so, that rationale disappeared when the Bretton Woods system collapsed in the early 1970s. Since then, even after the creation of $250bn in SDRs in 2009 to boost reserves and liquidity during the global financial crisis, they make up less than 4 per cent of non-gold global official foreign exchange reserves, less than half the level in the 1970s.