Retail sales fell 0.6 percent on the month at year-end. The decline followed a downwardly revised 0.3 percent increase in November and left volumes at their lowest level since last April. However, with base effects positive, annual workday adjusted growth still climbed from minus 1.5 percent to minus 0.8 percent, a 6-month high.

The monthly headline drop reflected losses in both food, alcohol and tobacco (1.4 percent) and in discretionary spending (0.8 percent). Indeed, the overall decrease would have been steeper but for a 1.0 percent rise in auto fuel.

The surprisingly soft December update leaves fourth quarter sales 0.3 percent below their third quarter level, implying a modest hit from the retail sector on GDP growth. More generally, it puts the Swiss RPI at 10 and the RPI-P at 5. Both readings show recent overall economic activity running just slightly ahead of market expectations.

Annual sales growth is forecast to rise from 0.7 percent to 1.1 percent.

Retail sales measure the total receipts at stores that sell durable and nondurable goods. The survey comprises around 4,000 companies with the small-sized firms asked to provide monthly turnover data on a quarterly basis. Statistics are provided in both nominal and volume measures; the latter is the more important for financial markets. The headline figure is the annual growth in sales volumes adjusted for differences in trading days. Seasonally adjusted monthly changes are also provided. Details are limited in the first estimate but a more complete picture is provided with the following month's release.

Consumer spending accounts for a large portion of the economy, so if you know what consumers are up to, you will have a pretty good idea on where the economy is headed. Needless to say, that is a big advantage for investors. The pattern in consumer spending is often the foremost influence on stock and bond markets. For stocks, strong economic growth translates to healthy corporate profits and higher stock prices. For bonds, the focus is whether economic growth goes overboard and leads to inflation. Ideally, the economy walks that fine line between strong growth and excessive (inflationary) growth. Retail sales not only give you a sense of the big picture, but also the trends among different types of retailers. Perhaps auto sales are especially strong or apparel sales are showing exceptional weakness. These trends from the retail sales data can help you spot specific investment opportunities, without having to wait for a company's quarterly or annual report.