Christine Lagarde announced Tuesday that she has resigned as managing director of the International Monetary Fund, effective from Sept. 12. Lagarde is set to take over as president of the European Central Bank on Nov. 1. In a separate statement, the IMF executive board said it had accepted Lagarde’s resignation. David Lipton will remain the acting managing director of the IMF during a search for a new leader. There has been speculation that Bank of England governor Mark Carney might replace Lagarde. In addition, George Osborne, the former chancellor of the UK exchequer and Bulgaria’s Kristalina Georgieava, the No. 2 at the World Bank, have been mentioned in various news reports. Since 1945, the IMF managing director has been from Europe.Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.