Conventional wisdom says that insiders and 10% owners really only buy shares of a company for one reason — they believe the stock price will rise and they want to profit. So insider buying can be an encouraging signal for potential investors, particularly during periods of uncertainty.

Insiders continued to add shares despite overall market volatility and economic uncertainty. The following are some of the most noteworthy insider purchases reported in the past week.

Continental Resources, Inc. CLR 7.13% says its founder and executive chair Harold Hamm picked up more than 3.43 million shares of this Oklahoma City-based company for $15.29 to $17.48 each. That totaled over $57.11 million and brought his stake to almost 5.18 million shares.

CEO Pablo Legorreta and other executives and directors at Royalty Pharma plc RPRX 4.84% bought into the initial public offering. The more than 1.67 million shares were priced at $28 each, and that totaled around $46.82 million. A 10% owner also purchased 3 million shares.

A director at Axis Capital Holdings Limited AXS 6.04% returned to add to his stake. The 575,000 shares of this specialty insurance provider indirectly scooped up, at prices ranging from $41.29 to $43.40, totaled more than $24.5 million. The stake was up to over 2.42 million shares.

A Groupon Inc GRPN 7.57% director indirectly purchased 250,000 shares of the Chicago-based online marketplace provider at prices ranging from $20.99 to $22.16 each. That totaled more than $5.39 million. The 34.13-million-share stake compares with a float of over 22 million.

A director at Cardtronics PLC CATM 8.14% recently picked up almost 209,000 shares of this ATM network operator. At an average price of $23.25 to $24.61 per share, that came to more than $5 million. Another director added 3,500 shares to a stake earlier in the month.

Fox Corp FOX 3.74% CEO Lachlan Murdoch bought almost 49,500 shares of this news and entertainment company last week. At $28.32 per share, that added up to more than $1.4 million. Pursuant to a transfer plan, those shares simultaneously were sold to a family trust at the same price.

A director paid an average of $16.03 each for more than 62,000 Epizyme Inc EPZM 6.11% shares. That cost him more than $994,100 and brought his stake in this late-stage biopharmaceutical company to about 82,600 shares.

The CEO sold some shares in the previous week.

And WesBanco Inc WSBC 5.49% saw a director add shares to his stake. At $20.38 to $20.87 a share, the 25,000 shares cost him more than $517,500, and it increased his stake to almost 213,000 shares. Note that another director sold almost twice as many shares early in the month.

Note that there also was some smaller amount of insider buying at utilities Consolidated Edison, Inc. ED 0.93% and Vistra Energy Corp VST 3.87% posted last week.