Mr Greenspan has spoken and initially the measured words of the chairman of the United States Federal Reserve seemed to have had the desired effect. Stock markets stabilised as his comments to the Senate banking committee were beamed into dealing rooms around the world.
A late sell-off in New York, however, has cast doubt on whether Mr Greenspan can once more usher in a period of greater financial stability. The markets remain very nervous about the quality of corporate earnings - something which will become clearer as America's major corporations report quarterly figures over the next ten days.
Mr Greenspan has tried to distinguish between the recent carnage on Wall Street and what is happening in the wider US economy. Most importantly, he has predicted that the world's largest economy will grow faster than expected this year, despite its many problems.
The succession of corporate scandals that has so undermined confidence in corporate America will taper off, he says. A "once-in-a-generation frenzy of speculation" that led to a breakdown in the regulatory system is now over, Mr Greenspan believes. One must hope he is correct. The health of the US stock market exerts a powerful influence on the consumer confidence that the Federal Reserve chairman has identified as a critical factor in the nascent US recovery.
In the meantime, America's woes continue to be Europe's gain. The euro remained above parity with the dollar yesterday, for only the second day in over two years. A stronger euro is a valuable psychological boost for the single currency with significant benefits for the eurozone's 308 million citizens as it puts off the prospect of a rise in interest rates.
But the revival of the euro comes with a health warning. The proximate cause of its recent rise may well also spell trouble on this side of the Atlantic. The economic recovery, underway in Europe, is primarily export led and the US is the most important market for European goods. Any reverse in the US economy puts our recovery at risk as demand for European imports will fall. Similarly, a weak dollar will push up the price of European goods in the US and third markets.
An out-of-favour dollar and a stalled US economy may be too high a price to pay for a resurgent euro. For this, and other reasons, we must hope that Mr Greenspan's predictions hold true and that his comments - along with other actions by the US authorities - have a long-term impact.