US GDP growth fell short of expectations in last year’s fourth quarter, the government reports. National output increased 2.6% in the final three months of 2014 vs. the previous quarter (seasonally adjusted annual rate). The consensus forecast was looking for something better—a 3.2% rise, according to Econoday.com’s survey of economists.

The soft number for headline growth in Q4 is a bit surprising when you look at the statistical elephant in the room, namely, consumer spending, which accounts for nearly 70% of GDP. Personal consumption expenditures accelerated to a 4.3% pace in the fourth quarter, a handsome improvement over Q3’s 3.2% rise. Meanwhile, disposable personal income growth accelerated to 3.8% in Q4 vs. 2.0% in Q3–a bullish sign for consumer spending in the near term.

So, why the lesser pace of growth for headline GDP? Part of the explanation is due to the slide in government expenditures, which fell 2.2% in Q4. That’s a fairly large reversal from Q3’s 4.4% gain. A faster growth rate for imports vs. exports—aka a bigger trade deficit–also weighed on headline GDP. Another corner of disappointment: business spending on equipment—a measure of corporate confidence in the economic outlook–slumped 1.9% in Q4, although it follows back-to-back gains of 11.0%-plus in each of the previous quarters and so some of this may be payback after a run of strength.

The good news is that the general trend in the private sector still looks encouraging. That’s not surprising, given the run of (mostly) upbeat monthly data published lately. I expect that today’s preliminary estimate of Q4 GDP will be revised up in the months to come. My GDP forecast from earlier this week–a relatively objective econometric reflection of data published to date–anticipated a 3.6% increase for today’s number. That’s obviously a bit too strong given today’s release. But considering that business-cycle risk for the US remains low at a time when the labor market has been expanding at a faster rate, today’s initial GDP data probably underestimates the economy’s forward momentum in last year’s final quarter.