Will an Upbeat Federal Reserve Burst the Market Bubble?

It's pretty clear by now just how dependent the global financial system is on the largesse of the world's central banks. The Federal Reserve, in particular, has taken on immense importance in the post-crisis world of ultra-low interest rates, aggressive stimulus measures and constant stock market activism.

So it's not surprising that markets — especially bonds and currencies — reacted negatively to Wednesday's upbeat and hawkish Federal Reserve policy statement, which opened the door to a new interest rate hike as soon as September. And while it's tempting to dismiss this as merely a pity party by liquidity junkies worried that Fed Chair Janet Yellen is going to prick their bubble, these folks could be justified in their concern.

After all, fundamentals seem to matter less and less (witness the five-quarter long U.S. corporate earnings recession and stretched stock valuations) while stimulus matters more and more. Remember Brexit? All the fear of a possible breakup of the European Union got washed away by non-specific hints, since walked back, of a "helicopter money" drop of coordinated fiscal/monetary spending out of Japan.

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The post-2009 bull market is fragile and very sensitive to any dramatic shift in policy. I'm not even talking about an aggressive rate hike campaign; merely a halt to asset purchase programs underway in Japan and Europe. Globally, the monthly pace of financial asset monetization has never been higher.

The high from the monetary morphine is easy to see. About a quarter of the global bond market is trading at negative interest rates (around $13 trillion worth). Stocks have been boosted by corporate share repurchases funded by cheap debt issuances. Recent strength in consumer spending, especially in autos and housing, depends on debt-servicing costs being so low.

Yet for reasons beyond the scope of this article — including everything from mal-investment in Chinese fixed assets to aging demographics in the West and a slowdown in investments needed to boost U.S. labor productivity — the medicine hasn't fixed the deep scars left from the housing crash.

Related: Home Prices Hit an All-Time High: Is This Another Bubble?​​

More debt was simply piled on. Systemic hurdles to healthy growth, everything from a lack of fiscal transfers and a banking union in Europe to needed reform of America's health care, educational, regulatory and tax systems, were kicked further down the road. Monetary policy normalization was also repeatedly delayed, creating moral hazard problems.