Image by Csaba Nagy from Pixabay.

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 from it. So insider buying can be an encouraging signal for potential investors, particularly when there is uncertainty in the markets or the markets are near all-time highs.

With the earnings reporting season underway, plenty of insiders are now adding to their stakes. Here are some of the most noteworthy insider purchases that were reported in the past week.

Snowflake Inc (SNOW) saw a 10% owner acquire over $39.31 million worth of shares this past week. That was more than 1.74 million shares costing between $219.61 and $235 apiece. Note that some other insiders sold more than 690,000 shares altogether last week as well.

A beneficial owner at cloud company Fastly Inc (FSLY) stepped up to the buy window early last week. That owner indirectly added 500,000 shares to its stake. At prices that averaged $65.41 per share, that totaled more than $32.07 million. In addition, an executive shed over 14,000 shares last week as well.

Recently, Executive Chair Rupert Murdoch acquired 500,000 News Corp (NWS) shares via trust. At prices ranging from $23.50 to $24.40 per share, the total came to over $12.04 million. Shares of this media company ended the week trading at $24.93, above Murdoch's purchase price range.

The almost 108,300 PennyMac Financial Services Inc (PFSI) shares that one director indirectly purchased this past week had prices ranging from $56.94 to $58.42 apiece. The transactions cost that director around $7 million altogether. The timing seems fortunate, as the stock closed the week trading at $65.70 a share.

As rumors about activist investor interest swirled, a Dropbox Inc (DBX) director indirectly purchased 100,000 shares of this San Francisco-based company. At prices of $24.51 to $24.58 per share, that totaled almost $2.46 million. The week's close at $27.06 indicates up to a 10% gain for that director.

After indirectly purchasing around 1.62 million Ironwood Pharmaceuticals, Inc. (IRWD) shares in the prior week, a director added another 225,000 last week. At $10.30 to $10.54 apiece, the latest transactions cost the director more than $2.33 million. The stock ended the week trading up at $11.31 a share.

Bucking a selling trend, a Parker-Hannifin Corp (PH) director scooped up 3,900 shares for $299.43 to $299.95 apiece. The total for these transactions was nearly $1.17 million. Note that the director's purchases were pursuant to a Rule 10b5-1 trading plan. The stock closed Friday at $312.56 per share.

ADT Inc (ADT) CEO David DeVries and another officer bought a combined 150,000 shares. The purchase prices ranged from $6.91 to $7.32 a share for this home and business security leader, which added up to around $1.16 million. An analyst upgrade pushed shares to $8.32 by week's end.

Microsoft Corporation (MSFT) and other tech and growth stocks were under pressure last week. Yet a director picked up 4,300 shares midweek for $236.80 apiece, which added up to almost $1.02 million. Note that this tech giant's chief executive parted with over 278,600 shares earlier this month.

And a director at Walmart Inc (WMT) added more than 7,700 shares to his stake early in the week. At share prices ranging from $129.54 to $129.72, that cost that director more than $1 million. With competition in the grocery space intensifying, the stock closed the week at $134.12, which represents a quick gain of up to 3.5% for that director.

Note that some smaller amount of insider buying at Archer-Daniels-Midland Co (ADM), Broadcom Inc (AVGO), Cerner Corporation (CERN), and Carrols Restaurant Group Inc (TAST) was reported in the past week, as well.