Recently, various executives have taken part in insider buying activity for the stocks of Tesla Motors Inc (NASDAQ:TSLA), SolarCity Corp (NASDAQ:SCTY), Cytokinetics, Inc. (NASDAQ:CYTK), and Halozyme Therapeutics, Inc. (NASDAQ:HALO).

Tesla Motors Inc

CEO Musk Elon bought 82,645 shares worth $20,000,090, at an average price of $242, as reported in the SEC filing on August 21. Following the insider-buying transaction, his stake in Tesla Motors has now grown to 28,371,342 shares with a value of $6,865,864,764. According to TipRanks.com, which measures corporate insiders’ success based on their transactions, Elon Musk has an average return of 190.8% and a 70.0% success rate. Musk is ranked #30 out of 33618 corporate insiders.

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SolarCity Corp

Additionally, as a director of SolarCity, Elon Musk bought 123,510 SolarCity shares today worth $4,999,685, at an average price of $40.48. Following the insider-buying transaction, his stake in SolarCity has now grown to 20,805,082 shares with a value of $772,076,593.

Cytokinetics, Inc.

Director Patrick Gage purchased 10,000 shares, valued $65,480, in multiple transactions dated August 20. After completion of the transaction, Gage owns 30,850 Cytokinetics shares, worth $202,006. According to TipRanks.com, which measures corporate insiders’ success based on their transactions, Patrick Gage has an average return of 177.7% and a 88.9% success rate. Gage is ranked #34 out of 33618 corporate insiders.

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Halozyme Therapeutics, Inc.

Laurie Stelzer bought 10,000 shares worth $172,300 at an average price of $17.24, in a transaction dated August 20. Ms. Stelzer joined Halozyme in June 2015 as Senior Vice President, Chief Financial Officer. At Halozyme, she is responsible for the Finance, IT, and Hylenex Commercial organizations. Most recently, Ms. Stelzer served as the Senior Vice President of Finance supporting R&D, Technical Operations and M&A at Shire, Inc.