Recent econometric estimates suggest that currency unions have far greater effects on trade patterns than previously believed. Since currency unions are good for trade, and trade is good for growth, that is one major argument in favor of EMU. If there were evidence that the boost to trade within EMU was likely to come in part at the expense of trade with outsiders, that would imply something stronger, for a neighbor such as the United Kingdom: that life outside EMU would get progressively less attractive in the future. But there is no such evidence, either for currency unions in general (according to Frankel–Rose) or for the first three years of EMU in particular (according to Micco, Stein, and Ordoñez). Furthermore, there are the usual countervailing arguments for retaining monetary independence, particularly the famous asymmetric shocks. One possible argument for waiting is that UK trade with euroland is still increasing, probably due to lagged effects of joining the EU and the Single Market initiative. Estimates suggest that the growing trade links in turn lead to growing cyclical correlation. The implication is that the UK may better qualify for the optimum currency area criteria in the future than in the past. On the other hand, if, as a result of waiting to enter, London loses to Frankfurt its position as the leading financial center in the European time zone, that loss may not be readily recoverable in the future.