* Insider buying can be an encouraging signal for potential investors. * Directors stepped up to make sizable share purchases last week. * Some of those transaction came in the wake of earnings reports.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 global economic gloom. Here are some of the most noteworthy insider purchases reported in the past week.Sysco Activist investor Nelson Peltz and one other SYSCO Corporation (NYSE: SYY) director each indirectly added 103,700 shares of this food services giant to their stakes. At per-share prices ranging from $50.29 to $52.27, that totaled more than $10.74 million altogether. Note that these two directors also purchased 600,000 shares each in the previous week.Sysco's disappointing fiscal third-quarter earnings posted earlier this month were followed by lowered price targets. The stock ended last week's trading at $51.75 per share, still within the above purchase price range. The share price is up more than 47% since its year-to-date low in March.Berkshire Hathaway Berkshire Hathaway Inc. (NYSE: BRK-B) saw a director purchase nearly 1,000 shares of this Omaha-based conglomerate last week at $173.30 per share. The same director also bought eight of the class A shares via family trust. Those cost $261,002.63 apiece. The total for these transactions was more than $2.26 million.CEO Warren Buffett has been uncharacteristically cautious so far this year. The B shares ended last week up about 3% to $175.07, while the A shares were last seen trading at $263,094.00 apiece. The timing of that director's purchases seems fortunate.Mercury General Mercury General Corporation (NYSE: MCY) founder and board chair George Joseph stepped up to the buy window again last week. He bought more than 84,000 shares for $38.72 to $38.86 apiece, which totaled almost $3.28 million. Joseph also purchased over 447,000 shares in the previous week.Shares of this Los Angeles-based insurer closed most recently at $39.24 a share. That is above the most recent purchase price range. It is also more than 10% higher than the year-to-date low during the pandemic panic selling back in March, and the analysts' consensus price target is up at $44.See also: Activist Investor Nelson Peltz Says He Is Putting New Capital To WorkIn addition, note that there was some amount of insider buying at Arch Capital Group Ltd. (NASDAQ: ACGL), Arconic Corp (NYSE: ARNC), Carrier Global Corp (NYSE: CARR) and Green Dot Corporation (NYSE: GDOT) last week as well.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.See more from Benzinga * Barron's Picks And Pans: Berkshire Hathaway, Carvana, Madison Square Garden And More * Bulls And Bears Of The Week: Caterpillar, Facebook, Microsoft And More * Barron's Picks And Pans: Berkshire Hathaway, Disney, SoftBank And More(C) 2020 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.