As investors cheer the good news for job growth that came with the February employment report, they may be overlooking a troublesome dynamic: A tightening jobs market, in combination with rising commodity costs, could stir inflation, cutting into corporate profits and forcing the Federal Reserve to become more hawkish.
On Friday, the nonfarm payrolls measure showed an increase of 175,000 jobs in February, well above the weather-dampened expectations. And though the unemployment rate ticked up to 6.7 percent from 6.6, the broadest measure of unemployment, the U-6, dropped slightly from 12.7 percent to 12.6 percent—the lowest reading since it was at that level in November 2008.
(Read more: Chart: What's the real unemployment rate?)
Since the U-6 counts all unemployed workers, plus marginally attached workers and workers employed part-time for economic reasons, it could be a better measure of the remaining supply in the labor market. The decrease in the U-6 could thus indicate that the "slack" in the labor force—which allows companies to hire more workers without paying more—is decreasing. Once the slack is gone, wage inflation tends to follow.
"Measuring slack is not an easy thing, but an unemployment rate of 6.7 tells you there's a lot less slack than there used to be," said Peter Boockvar, chief market analyst at the Lindsey Group. "The idea that all of the people who dropped out of the labor market will magically come back just doesn't make sense—particularly for the low-end worker who is now enjoying a lot of government benefits. Therefore, the labor market is getting tighter than the Fed thinks."
As a result, "the inflation trend is going to start moving higher. It's not a single event that will happen—it's a process. But it's definitely worth watching," he said.
(Read more: Jobs report signals higher interest rates ahead)
The other factor that could contribute to this trend is the recent rise in commodity prices. The CRB commodity index, a broad measure of prices, has risen some 10 percent this year. It's at its highest level in over a year, due to tough agriculture conditions and winter weather issues that have sharply increased the prices of many commodities. More recently, the crisis in Ukraine seems to have boosted prices of commodities such as wheat and corn.
"Increasing commodity prices will drive a rise in inflation," predicted Kathy Lien, managing director of FX strategy at BK Asset Management. "It's a natural reaction to the recent growth as well as the geopolitical uncertainly that is happening in the global economy."