The dollar has taken a surprisingly big stumble in recent weeks, prompting traders to ask: What’s really driving the selloff? The answer some are coming up with smacks of conspiracy theory. Rumors are flourishing that global policy makers made a secret deal at the G-20 meeting in Shanghai late last month. This “Shanghai Accord” to weaken the greenback was aimed at calming the financial markets, which had gotten off to an awful start to the new year, according to the chatter. No foreign-exchange pact was announced at the February meeting of central bankers and policy makers from the 20 largest economies. That hasn’t ... (full story)