More countries in Europe are selling debt — and debt maturing in more than a few months, at negative yields, meaning investors are actually paying a country to hold onto their money. Germany recently sold 2-year schatz at a negative yield, and the Netherlands, Denmark, Finland and Switzerland have also all sold debt at negative yields. The situation is pretty good for governments borrowing money. But the trend signals rising worries about the future of the euro zone and the euro, said Marc Chandler, global head of currency strategy at Brown Brothers Harriman.