Schlumberger (SLB) was Smart Insider's stock pick of the week after the company's Executive Vice President Abdellah Merad sold 60,000 Schlumberger shares at $41.90 apiece on Oct. 24.

The transaction, which reduced Merad's stake in the company by 22% to 212,000 shares, followed a 50,000 share sale in February for $48.52 per share, Smart Insider said in a note Tuesday.

"The stock has moved lower and it is concerning to see a large % sale from a key operating officer at a lower price point and while the stock is near its 52-week low," according to the note.

Smart Insider downgraded the stock further to -1, or strongly negative signal, from -N, or notable and negative signal, in July.

Price: 41.50, Change: +0.11, Percent Change: +0.27