Wall Street is off to a rocky start at Friday's Opening Bell after a disappointing GDP report. The U.S. economy grew 2.6% in the last three months of 2014. That's much slower than the 3% growth, economists had expected. Consumer spending, however, jumped at a 4.3% rate in the fourth quarter, the fastest pace in about 9 years. Shake Shack (SHAK) debuts today on the New York Stock Exchange (ICE). The burger joint priced its IPO at $21 a share, above the expected range. The company is offering 5 million shares to raise $150 million. Shares of Mattel (MAT) are dropping in early trading. The toymaker missed its Q4 earnings estimates. Sales of Barbie dolls tumbled 12% and its Fisher-Price brand fell 11%.