Stock futures are falling as investors continue a pullback after a two-month stretch of nearly unbroken gains.
Overseas markets also stumbled, with many Asian and European indexes down by more than 1 percent. Renewed worries about a possible default by Greece on its debt sent shares lower.
Still, there's hope for bulls. Reports on initial U.S. jobless claims and monthly retail sales could send the market back upwards.
Dow Jones industrial average futures are down 29, or 0.3 percent, at 10,820. Standard & Poor's 500 index futures are down 3.60, or 0.3 percent, at 1,175.40, while Nasdaq 100 index futures are down 4.50, or 0.2 percent, at 1,970.50.
Other factors dampening market sentiment: Disappointing data showing that consumer credit in the U.S. fell by $11.5-billion in February, and a suggestion from Thomas Hoenig, a rate-setter at the U.S. Federal Reserve, that borrowing costs should start rising soon.
In Europe, the FTSE 100 index of leading British shares was down 67.15 points, or 1.2 percent, at 5,694.91 while Germany's DAX fell 75.65 points, or 1.2 percent, at 3,959.29. The CAC-40 in France was 67.71 points, or 1.7 percent, lower at 3,959.26.
The main point of interest ahead of the European Central Bank rate decision is what is going on with Greek borrowing costs in the money markets. Earlier, the spread between Greek and German 10-year bond yields widened to 4.4 percentage points earlier, its highest level since the euro was introduced in 1999. The higher the spread, the less confidence markets are showing in Greece's ability to pay.
Particularly worrying is that the spread between the Greek and German 2-year bonds swelled by a staggering 1.2 percentage points Thursday as investors demanded more interest just to hold Greek debt. Greek shares took another battering - the benchmark ASE composite index was down around 5 percent.
In Asia, Tokyo's Nikkei index slipped 1.1 percent to 11,168 points after reaching an 18-month high this week.
But there is underlying support in regional stock markets with top Asian companies at their most optimistic since the global financial crisis nearly two years ago.
A Reuters check-up of 100 leading Asian companies, from Japan to India, showed government stimulus-fuelled recovery across Asia had filtered through to the corporate sector, with the technology and resources industries leading the pack. Fifty-nine had a 'positive' to 'very positive' rating on their six-month outlook, its highest since Reuters started the review in mid-2009 and up from 38 in the December review.