* Insider buying can be an encouraging signal for potential investors when markets face uncertainty. * Insider purchases of biopharmaceutical company and specialty retailer shares were reported last week. * Some insiders took advantage of initial public an secondary offerings as well.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, as there has been due to the pandemic resurgence and political issues.Here are some of the most noteworthy insider purchases that were reported in the past week, as the year winds down and investors ponder the new year.The recent Bioatla Inc (NASDAQ: BCAB) IPO encouraged a former 10% owner and a director to buy in. The almost 2.19 million shares they acquired altogether at $18 per share added up to around $39.4 million. Shares of this San Diego-based biopharma company ended last week’s trading at $31.82 apiece.Daniel Loeb, a 10% owner, purchased a big block of Upstart Holdings Inc (NASDAQ: UPST) shares at the initial public offering price of $20 apiece. The total for the 1.20 million shares of this cloud-based lending platform operator that owner acquired added up to $24 million. The shares ended the week’s trading at $43.96 apiece, after hitting a post-IPO high of $51.40.GameStop Corp. (NYSE: GME) recently saw a beneficial owner indirectly acquire almost $757,000 shares of this specialty retailer. Prices ranged from $14.77 to $16.02 per share. The transactions added up to more than $19.02 million and raised the stake to approximately 9 million shares. The stock closed most recently at $20.15, above the owner’s purchase price range.A director at Arvinas Inc (NASDAQ: ARVN) indirectly purchased over 142,800 shares of this New Haven, Connecticut biopharmaceutical company in a secondary offering. At the offering price of $70 per share, the total for this transaction came to nearly $10 million. Shares were last seen trading at more than $82.A Foot Locker, Inc. (NYSE: FL) 10% owner returned last week to purchase over 108,200 more shares of this specialty retailer at $38.12 to $39 apiece. That totaled almost $4.2 million, and it raised that stake to more than 12.93 million shares. Note that his owner has bought more than 761,400 shares so far this month. The stock closed most recently at $39.49.CEO Kevin Tang stepped up to the buy window last week and paid $14.05 to $15.79 each for more than 275,700 Odonate Therapeutics Inc (NASDAQ: ODT) shares. That cost him over $4.18 million, and it brought his stake in this San Diego-based company to more than 15.51 million shares.Services provider to the financial industry, Jack Henry & Associates, Inc. (NASDAQ: JKHY), saw a director add 8,900 more shares to his stake last week. At $155.61 to $156.70, that totaled more than $1.39 million, and it brought his stake to more than 32,800 shares. The stock last closed at $157.69.The NetApp Inc. (NASDAQ: NTAP) chief financial officer has acquired 15,000 shares. At prices ranging from $63.51 to $64.24 a share, that cost him more than $958,300. The cloud computing company’s stock hit a new 52-week high of $67.63 a share afterward. Note that some of the shares were purchased under an employee stock purchase plan.And Guidewire Software Inc (NYSE: GWRE) had a director indirectly purchase shares at a time when other insiders were selling. The 6,000 shares that director picked up cost him more than $746,900, at per-share prices ranging from $124.45 to $124.50. The stock ended last week at $127.21 a share.See also: Insider Sells Nucor’s StockNote that there also was some smaller amount of insider buying at Coupa Software Inc (NASDAQ: COUP), Eos Energy Enterprises Inc (NASDAQ: EOSE), Greif, Inc. (NASDAQ: CURI), Mustang Bio Inc (NASDAQ: MBIO) and Vistra Corp (NYSE: VST).At the time of this writing, the author had no position in the mentioned equities.Keep up with all the latest breaking news and trading ideas by following Benzinga on Twitter.Photo via BentleyMall on Wikipedia. See more from Benzinga * Click here for options trades from Benzinga * Benzinga’s Bulls And Bears Of Christmas Week: Airbnb, Apple, Netflix, Nike, Tesla And More * Barron’s Picks And Pans: Bank Mergers, Comcast, Dogs of the Dow, Square And More(C) 2020 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.