Wall Street Journal reports that The calm in China's currency is making some investors uneasy. Twice in the past year, sudden drops in the value of the yuan have rattled global markets, sparking concerns that a deeper decline was at hand as officials struggle to orchestrate an economic "soft landing" following years of debt-fueled growth. Since then, the People's Bank of China has calmed the waters by improving communications and the government has increased stimulus in a bid to stabilize growth. The Federal Reserve's decision to delay rate increases has kept a lid on the value of the U.S. dollar, relieving some of the pressure on the yuan. Yet in a refrain familiar by now to investors the world over, analysts are worrying that stimulus alone won't be enough to get China's growth back on track and support the yuan indefinitely. Fundamental indicators of Chinese economic health continue to deteriorate, a sign to skeptics that the currency remains overvalued and a reminder of the challenges facing the world's second-largest economy. "China has done a good job in anchoring market expectations and using all the tools in its policy toolbox to stabilize the economy, but it hasn't fixed the underlying problems," said David Loevinger, a managing director at TCW Group, which has $194.6 billion of assets under management.