Are OECD Imports diversifying or re-concentrating?

This paper explores the evolution of OECD imports over time and as a function of income levels, measuring the concentration of those imports across origin countries at the product level. We find evidence of diversification followed, in the very last years of the sample period (post-2000), by a slight reconcentration. This reconcentration is entirely explained by the growing importance of Chinese products in OECD imports. We also find evidence of relatively more volatile concentration levels for differentiated goods, consistent with a simple model of adverse selection and screening of suppliers by OECD buyers. Finally, we find that “accession” to OECD markets occurs directly (rather than after acquiring prior export experience on other markets) for about half of the (extra-OECD) exporter/product pairs, but that one to four years of experience enhances subsequent survival on OECD markets.