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. Here are some of the most noteworthy insider purchases reported in the past week.

Nkarta, Inc. (NTX) saw a number of beneficial owners buy into the initial public offering, including GlaxoSmithKline plc. (GSK). Altogether, they picked up more than 9.83 million shares of this biopharmaceutical company for $18 each. That totaled nearly $187 million.

Two Akero Therapeutics Inc. (AKRO) beneficial owners recently took advantage of a secondary offering to buy 830,000 shares altogether of this California-based company, at $36 each. That totaled $29.88 million. A different 10% owner sold shares earlier this month.

A beneficial owner of WESCO International, Inc. (WCC) returned last week to add to their stake. The 300,000 shares of this industrial supplier that were scooped up, at prices ranging from $35.69 to $37.50, totaled more than $10.97 million. That same owner bought about 662,800 shares in the prior week.

A 10% owner at Trinseo S.A. (TSE) indirectly picked up over 310,500 shares of this plastics manufacturer last week. At an average price of $21.81 per share, that came to more than $6.77 million. That same insider also sold some shares in June, when they traded above $23.

Three directors at Poseida Therapeutics, Inc. (PSTX) bought into that initial public offering. The 270,000 shares of this San Diego-based company were priced at $16 each. The total for these transactions came to $4.32 million. One of those directors was also a 10% owner.

Perspecta Inc. (PRSP) CEO John Curtis and another director together bought more than 22,900 shares of this IT services provider last week. At $21.43 to $22.24 per share, that added up to more than $503,900. These purchases were pursuant to Rule 10b5-1 trading plans.

CEO Thomas Ferguson paid an average of $28.94 for 10,000 AZZ Inc. (AZZ) shares, and another executive bought 5,500 shares for $30.76 to $30.91 apiece. Altogether, it cost them more than $458,900 to bulk up their stakes in this Fort Worth, Texas-based industrial.

A Bed Bath & Beyond Inc. (BBBY) saw a director add shares to her stake. At $7.88 to $7.90 a share, the 34,000 shares cost her more than $268,200 and increased the stake to over 42,000 shares. Note that another director bought 6,000 shares in the previous week.

Note that there also was some smaller amount of insider buying at NVIDIA Corporation (NVDA), Science Applications International Corp. (SAIC), Texas Pacific Land Trust (TPL) and Westrock Co. (WRK) posted last week.