All OECD countries view generic and biosimilar markets as an opportunity to increase efficiency in pharmaceutical spending, but many do not fully exploit their potential. In 2021, generics accounted for more than three‑quarters of the volume of pharmaceuticals sold in Chile, Germany, New Zealand, the United Kingdom, the Netherlands, Canada and Latvia, but less than one‑quarter in Switzerland and Luxembourg (Figure 9.7). In value, generics accounted for more than two‑thirds of the pharmaceuticals sold in Chile in 2021, but on average only one‑quarter across OECD countries. Differences in market structures (notably the number of off-patent medicines) and prescribing practices explain some cross-country differences, but generic uptake also depends on policies (OECD, 2018[1]). In Austria, for example, generic substitution by pharmacists is not permitted, while in Luxembourg, generic substitution by pharmacists is limited to selected medicines. In some countries, such as Ireland, generic penetration is low but originators and generics may be priced at the same level.