Stocks finished the first week of 2018 with another strong performance. The Dow Jones Industrial Average (^DJI -1.24%) and the S&P 500 (^GSPC -1.46%) both closed at record highs.

Today's stock market

Index Percentage Change Point Change
Dow 0.88% 220.74
S&P 500 0.70% 19.16

Data source: Yahoo! Finance.

Tech stocks led the rally today, with the Technology Select Sector SPDR ETF (XLK -1.62%) moving ahead 1.1%. Energy shares took a breather from their recent run; the SPDR S&P Oil & Gas Exploration & Production ETF (XOP -1.18%) slipped 0.6%.

As for individual stocks, Barnes & Noble (BKS) fell sharply on disappointing holiday sales, and Momenta Pharmaceuticals (MNTA) jumped after the company reported positive results from a drug trial.

Rising stock graph and columns of numbers.

Image source: Getty Images.

No joy this holiday season for Barnes & Noble

Bookseller Barnes & Noble reported a decline in holiday sales that was worse than expected, and its stock plummeted 14.2%. Sales for the nine weeks ending Dec. 30 fell 6.4% to $953 million. Comparable-store sales also declined 6.4%, with decreases in the gift, music, and DVD categories accounting for nearly half the comps contraction. Falling traffic in physical stores was the reason behind the drop in comparable sales, but that wasn't the only problem; online sales also slumped 4.5%.

Sales declines are certainly nothing new for Barnes & Noble, but making the December news even worse was the fact that management was sounding an upbeat note about the holiday season as recently as the second-quarter conference call on Nov. 30. CEO Demos Parneros guided to flat comps for the second half and a full-year decline in the low single digits. Instead, the company now expects comps to fall mid-single digits in fiscal 2018.

The profit picture for the full year dimmed as well. In the conference call a month ago, Parneros said the company was confident it would earn $180 million in EBITDA for the year. Now Barnes & Noble expects EBITDA to be in the range of $140 million to $160 million.

The company is working on a number of initiatives to try to turn things around: reducing the underperforming non-book offerings, trying to attract more customers to its in-store cafes, trying to grow its membership program, and, of course, implementing a cost-cutting program. But its numbers from the crucial holiday season seem to indicate more trouble ahead.

Momenta reports positive trial results

Shares of biotech Momenta Pharmaceuticals soared 19% after the company reported positive results from an early clinical trial of a drug for autoimmune diseases, designated M281.

The purpose of the trial with healthy adult volunteers was to assess the safety of the treatment and to determine whether the mechanism of its action worked as expected. M281 is a monoclonal antibody designed to reduce levels of the pathogenic autoantibodies that facilitate the tissue damage and organ dysfunction that are the hallmarks of autoimmune diseases. No serious adverse effects were observed, and levels of circulating immunoglobulin G (IgG) were reduced up to 89% in the 98-day study.

"I could not be more pleased that M281's ability to lower IgG to target levels with a favorable safety profile worked precisely as we had designed," said CEO Craig Wheeler in the press release. "These data support M281's potential as a best-in-class anti-FcRn therapeutic for the high unmet medical needs in immune-mediated disorders."

Momenta stock has been under pressure recently as the company's lead drug, a generic version of Copaxone, has come under competitive pressure and development efforts for two biosimilar drugs have experienced setbacks. Commercialization is still a long way off for M281, as the drug hasn't even been tested on sick people yet, but any good news at all was enough to have Momenta investors cheering today.