Stocks: 4 things to know before the open

premarket stocks trading
Click chart for in-depth premarket data.

Blame Switzerland for casting a dark shadow over the markets.

Here are the four things you need to know before the opening bell rings in New York:

1. Stocks keep falling: The Swiss stock market is still tumbling Friday, with the benchmark index off by more than 5% as investors consider the long-term implications of Switzerland's surprise decision to let its currency float freely instead of pinning it to the euro.

"The market is on high alert as we come into this session, looking out for further ripples from this shocking currency move," said Tom Beevers, CEO of StockViews in London. Most major stock markets across Europe are edging lower in early trading.

U.S. stock futures are also moving down, but the losses are muted.

Swiss companies, and currency brokers, are still licking their wounds after the surprise move on Thursday led the franc to shoot up in value and pushed Swiss stocks down by nearly 10%.

2. Earnings: Wall Street is preparing for more earnings to come through Friday.

Goldman Sachs (GS), PNC (PNC), and SunTrust Banks (STI) will report quarterly results before the opening bell.

Related: Fear & Greed Index

3. Economics: Official eurozone data confirms that prices fell across the region by 0.2% last month, marking the first time the area has experienced deflation since the Great Recession.

In the U.S., the Bureau of Labor Statistics will report December's consumer price index at 8:30 a.m. ET.

The University of Michigan's consumer sentiment index comes out at 9:55 a.m.

Related: CNNMoney's Tech30

4. The week in stocks: Wall Street trading has been downright depressing this week.

The Dow Jones industrial average, the S&P 500 and the Nasdaq have been awash in red, declining every single day this week.

Over the past five consecutive trading days, the major U.S. indexes have all fallen by over 3%.

CNNMoney Sponsors