While this week proved to be a rough one for investors, it brought the insiders rushing to the buy desk, as the insider purchases jumped dramatically this week. With just six trading weeks remaining in 2015, and a dip in the market providing better purchase points, the volume was about the highest we have seen this fall.

We cover insider buying every week at 24/7 Wall St., and we like to remind readers that while insider buying is usually a very positive sign, it is not in of itself a reason to run out and buy a stock. Sometimes insiders and 10% owners have stock purchase plans set up at intervals to add to their holdings. That aside, it still remains a positive indicator.

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Here are some of the companies that reported notable insider buying this past week.

Cheniere Energy Inc. (LNG) had a Wall Street legend purchasing more stock last week. Activist investor Carl Icahn bought an additional 1 million shares of the company at prices that ranged from $45.17 to $45.97 per share. The total for the buy came to $45.5 million. Cheniere engages in the liquefied natural gas (LNG) related business. The stock was trading midday Friday at $44.85.

Seattle Genetics Inc. (SGEN) hits the tape once more, and again it is biotechnology hedge fund Baker Brothers Advisers adding to its already huge position in the company. The fund bought an additional 934,624 shares at prices that fell between $41.31 and $44.00 apiece. The total for the massive buy came to $40.1 million. Seattle Genetics is a biotechnology company that develops and commercializes antibody-based therapies for the treatment of cancer. Shares were trading on Friday at $43.27.

Restaurant Brands International Inc. (QSR) had two directors at the company purchasing stock this past week. The pair bought a total of 252,600 shares at prices between $34.88 and $35.77. The total for the buy came to a very solid $8.7 million. The company owns and operates quick service restaurants under the Burger King and Tim Horton's brand names. As of October 8, 2015, it franchised or owned approximately 19,000 restaurants in approximately 100 countries and U.S. territories worldwide. The stock was trading on Friday at $36.12.

Angie's List Inc. (ANGI) has been under pressure, and a 10% owner stepped in last week and added to its position. TCS Capital Management bought 396,676 shares at prices that ranged from $7.36 to $7.67. The total for the buy came to an even $3 million. Angie's List operates a local services marketplace and consumer review site in the United States. It provides a marketplace to research, shop for and purchase local services for home, health and automotive service needs. Shares were trading on Friday at $9.23, so a well-timed buy.