decades. consumers, by contrast, have generally had much more limited exposure to, and interest in, global currency use, except in “ dollarized ” or “ euroized ” economies where the us dollar or the euro, are, or were, formal or informal means of payment in lieu of the domestic currency. https : / / www. ecb. europa. eu / press / key / date / 2019 / html / ecb. sp190917 ~ 9b6... 18. 09. 2019 digital challenges to the international monetary and financial system page 3 of 8 this has changed, however. the most recent wave of globalisation, in conjunction with the rapid evolution of online services, has supported consumer demand for payment services that work across borders and that are also faster, cheaper and easier to use. global tourism flows, for instance, have doubled over the past 15 years. the number of internet users has doubled too, as has the number of mobile phone users. the cost of sending data has shrunk considerably and access to more convenient services has widened. and in just ten years, global remittances have increased by over 50 %, while cross - border e - commerce activity has trebled. it is only natural, then, that new and emerging private payment solutions are mainly targeting consumers and workers, not merchants. consumers and workers constitute a much larger pool of potential users, with the associated network effects, which has meant that existing digital initiatives have been adopted much more quickly. consider m - pesa. it has revolutionised payments by making it possible to settle low - value transactions without a bank account. the volume of mobile money transactions in kenya has trebled in less than seven years and today already accounts for half of the country ’ s gdp. advanced economies are only starting to catch up with kenya. in china, alipay and wechat pay, two payment solutions developed by domestic bigtech firms, have attracted almost one billion customers each in less than ten years. bigtech payment services account for 16 % of gdp in china, higher than anywhere else. third - party mobile payment transactions last year in china were 15 times larger than in 2015. the available evidence therefore suggests that transaction and switching costs are much smaller in the case of retail consumer payments than they are for traditional currencies used for wholesale cross - border trade and finance. there is little reason to believe that such network effects would be less powerful for global networks, possibly making international currency

there is overlap between facebook ’ s family of products ; an estimated 2. 7 billion users use facebook, instagram, whatsapp or messenger each month. see cœure, b. ( 2019 ), “ update from the chair of the g7 working group on stablecoins ”, update to the g7 finance ministers and central bank governors meeting 17 - 18 july 2019, chantilly, france. see ministere de l ’ economie et des finances and bundesministerium der finanzen ( 2019 ), “ joint statement on libra ”, helsinki, 13 septembre 2019. see cœure, b. ( 2019 ), “ the euro ’ s global role in a changing world : a monetary policy perspective ”, speech at the council on foreign relations, new york city, 15 february 2019. see e. g. maggiori, m., neiman, b. and schreger, j. ( 2019 ), “ the rise of the dollar and fall of the euro as international currencies ”, aea papers and proceedings, vol. 109, american economic association, pp. 521 - 526. see, for example, krugman, p. ( 1984 ), “ the international role of the dollar : theory and prospect ”, exchange rate theory and practice, national bureau of economic research, university of chicago press, pp. 261 - 278. for historical evidence see eichengreen, b., mehl, a. and chitu, l. ( 2017 ), how global currencies work – past, present and future, princeton university press. moreover, gita gopinath and jeremy stein provide a unified theory for why a currency may be used dominantly in global trade and finance, where its role as an invoicing unit of international trade transactions is complementary to its role as a safe store of value ; gopinath, g. and j. stein ( 2018 ), “ banking, trade, and the making of a dominant currency ”, nber working paper, no. 24485. see bindseil, u. ( 2018 ), “ pre - 1800 central bank operations and the origins of central banking ”, mimeo. see also portes, r. and rey, h. ( 1998 ), “ the emergence of the euro as an international currency ”, economic policy, vol. 13, no 26, pp. 307 - 343. according to a seminal