The 'Initial' Estimate for Q4 GDP, to one decimal, came in at 2.6% (2.59% to two decimal places), a decrease from 3.4% for the Q3 Third Estimate. Investing.com had a consensus of 2.6%.

Here is the slightly abbreviated opening text from the Bureau of Economic Analysis news release:

Released by the Bureau of Economic Analysis. In the third quarter, real GDP increased 3.4 percent.

Due to the recent partial government shutdown, this initial report for the fourth quarter and annual GDP for 2018 replaces the release of the "advance" estimate originally scheduled for January 30th and the "second" estimate originally scheduled for February 28th. See the Technical Note for details.

The Bureau emphasized that the fourth-quarter initial estimate released today is based on source data that are incomplete or subject to further revision by the source agency (see “Source Data for the Initial Estimate” on page 3). Updated estimates for the fourth quarter, based on more complete data, will be released on March 28, 2019. [Full Release]

Here is a look at Quarterly GDP since Q2 1947. Prior to 1947, GDP was an annual calculation. To be more precise, the chart shows is the annualized percentage change from the preceding quarter in Real (inflation-adjusted) Gross Domestic Product. We've also included recessions, which are determined by the National Bureau of Economic Research (NBER). Also illustrated are the 3.22% average (arithmetic mean) and the 10-year moving average, currently at 2.07%.

Here is a log-scale chart of real GDP with an exponential regression, which helps us understand growth cycles since the 1947 inception of quarterly GDP. The latest number puts us 13.5% below trend.

A particularly telling representation of slowing growth in the US economy is the year-over-year rate of change. The average rate at the start of recessions is 3.35%. Four of the eleven recessions over this timeframe have begun at a higher level of current real YoY GDP.

In summary, the Q4 GDP 'Initial' Estimate of 2.6% was as expected and worse than the Q3 Third Estimate.