Those stellar fourth-quarter GDP numbers were better than the initial 5.7% growth estimate that came down last month, but economists have a warning: don’t expect it to last through the year. Exchange traded funds (ETFs) seem to be reacting to the report with caution, rather than exuberance.

Today’s fourth-quarter GDP numbers indicating 5.9% growth in the economy are a slight improvement over the previous 5.7% reported. But don’t get too comfortable with that. Economists expect that the numbers for this quarter will ultimately be much slower, judging by other numbers that have emerged in recent days.

January sales of previously occupied homes declined 7.2%, surprising economists, who expected a slight increase. These numbers are hot on the heels of Tuesday’s report on new home sales, which plummeted a whopping 11% in January. The numbers are being taken as a signal that tax credits may ultimately not be enough. iShares Dow Jones U.S. Home Construction (NYSEArca: ITB) is flat this mornig; in addition to owning homebuilders, the fund also holds retail stores that benefit when Americans purchase or upgrade homes. [Real Estate ETFs: On the Mend, or Trouble Ahead?]

Americans are becoming increasingly frustrated at the lack of growth in the job market, so it’s no surprise that consumer sentiment dove this month. At least outright panic over layoffs has abated, but lasting confidence may not come until a jobs stimulus package comes down and growth returns. [5 ETFs to Play the New Retail Climate.]

Business activity is picking up the pace, rising more than expected this month to the fastest pace in nearly five years. The barometer is perched at 62.6; any reading above 50 signals expansion.

Things seem to be improving at AIG (NYSE: AIG): the nation’s largest insurer reported an $8.9 billion loss. It sounds bad, until you recall that it’s an improvement over last year’s $62 billion quarterly loss a year earlier. PowerShares Dynamic Insurance (NYSEArca: PIC) is flat this morning. [Why Banks May Be the Next Big Movers.]

European Union officials, the International Monetary Fund (IMF) and the European Central Bank have all been in Greece this week to examine the country’s efforts at slashing its deficit. The goal? Slash the massive budget deficit by 4% this year. If Greece doesn’t come up with a plan, the euro could continue to suffer and financial uncertainty and fear about the region could have a worldwide contagion effect. CurrencyShares Euro Trust (NYSEArca: FXE) is up nearly 1% this morning.

Read the disclaimer, as Tom Lydon is a board member of Rydex|SGI.

The opinions and forecasts expressed herein are solely those of Tom Lydon, and may not actually come to pass. Mr. Lydon serves as an independent trustee of certain mutual funds and ETFs that are managed by Guggenheim Investments; however, any opinions or forecasts expressed herein are solely those of Mr. Lydon and not those of Guggenheim Funds, Guggenheim Investments, Guggenheim Specialized Products, LLC or any of their affiliates. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.