When the economy gets rocky, investors often turn away from riskier alternatives to the world’s safest and most risk-free investment, the debt securities issued by the U.S. federal government, in what is often described as a “flight to quality.”

The same phenomenon holds true for the world’s central banks, where the primary financial institutions of a number of nations have loaded up on U.S. Treasuries in recent years as their economies have faltered.

So what are we to make when the exact opposite scenario is happening today? Previously, we’ve noted that China has been selling off its U.S. government-issued debt holdings, but now the Wall Street Journal reports that the central banks of a number of other nations have joined in the selling frenzy of foreign held U.S. Treasury securities:

Central banks around the world are selling U.S. government bonds at the fastest pace on record, the most dramatic shift in the $12.8 trillion Treasury market since the financial crisis.

Sales by China, Russia, Brazil and Taiwan are the latest sign of an emerging-markets slowdown that is threatening to spill over into the U.S. economy. Previously, all four were large purchasers of U.S. debt.

Few analysts expect much higher yields in the Treasury market as a result. Foreign private purchases of U.S. debt have increased amid pessimism about the world economic outlook. U.S. firms and financial institutions continue to buy Treasurys, as do some foreign central banks….

In the past decade, large trade surpluses or commodity revenues permitted many emerging-market countries to accumulate large foreign-exchange reserves. Many purchased U.S. debt because the Treasury market is the most liquid and the U.S. dollar is the world’s reserve currency.

While the large scale sale of these foreign-held U.S. Treasury securities would ordinarily place upward pressure on the yields, or interest rates, that the U.S. Treasury must offer to lenders according to the laws of supply and demand, these sales have had little effect on the yields of U.S. government-issued debt securities.

Most likely this is due to the yields on U.S. Treasury securities being held down because U.S. firms and financial institutions have increased their purchases of U.S. government-issued debt in response to new regulatory requirements implemented one year ago, which mandated that they must maintain a set minimum percentage of their investment holdings in high quality, liquid assets.

Although those new regulations took effect in September 2014, the WSJ article describes how the U.S. government debt holdings of U.S. investors, firms and institutions have changed in the current year to date:

U.S. bond mutual funds and exchange-traded funds targeting U.S. government debt have attracted $20.4 billion net cash this year through the end of September, poised for the biggest calendar-year inflow since 2009, according to fund tracker Lipper.

Recall that 2009 was the worst year for the Great Recession, and was characterized by a worldwide flight to quality to U.S. Treasury securities, as investors fled the risk of great losses in other markets.

In 2015, however, the situation is different. It would be one thing if U.S. investors, firms, and financial institutions were completely free to choose how to invest their own funds and were choosing to plow them into U.S. Treasury securities because they believe these are the best available investment option. But one wonders what opportunity costs they are paying because they are instead being compelled by the U.S. government to load up on U.S. government-issued debt. After all, if over the past year they had been free to invest in more profitable opportunities that might provide them with a better rate of return, wouldn’t the U.S. economy be performing better than it is?

These kinds of dynamics help demonstrate how excessive government spending sustained by borrowing is weighing down the nation’s potential for greater real economic growth today and increasing the heavy burden of government on regular Americans.