Insider buying decreased significantly last week with insiders buying $38.86 million of stock compared to $269.24 million in the week prior. Selling also decreased significantly with insiders selling $635.25 million of stock last week compared to $1.33 billion in the week prior.

This muted activity is not unusual as we approach the end of the quarter and most companies enter a quite period when insiders cannot purchase or sell their stock. Insider buying in our previous report was dominated by biotech stocks and this week is no different with biotech stocks accounting for three of the five top purchases. Amongst the insider purchases OvaScience (OVAS) and Flex Pharma (FLKS) stood out because both were purchased by their CEOs indirectly through the venture capital firm Longwood Fund. Both these CEOs are also co-founders and Partners of Longwood Fund.

Sell/Buy Ratio: The insider Sell/Buy ratio is calculated by dividing the total insider sales in a given week by total insider purchases that week. The adjusted ratio for last week went up to 16.35. In other words, insiders sold more than 16 times as much stock as they purchased. The Sell/Buy ratio this week compares unfavorably with the prior week, when the ratio stood at 4.93. We are calculating an adjusted ratio by removing transactions by funds and companies and trying as best as possible only to retain information about insiders and 10% owners who are not funds or companies.

Note: As mentioned in the first post in this series, certain industries have their preferred metrics such as same store sales for retailers, funds from operations (FFO) for REITs and revenue per available room (RevPAR) for hotels that provide a better basis for comparison than simple valuation metrics. However metrics like Price/Earnings, Price/Sales and Enterprise Value/EBITDA included below should provide a good starting point for analyzing the majority of stocks.

Notable Insider Buys:

1. Seattle Genetics, Inc. (SGEN): $34.68

Director Felix Baker acquired 124,065 shares of this biotech company, paying $31.85 per share for a total amount of $3.95 million. These shares were purchased indirectly by Baker Bros. Advisors LP.

You can view the list of recent insider transactions for Seattle Genetics, Inc. here.