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 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.

A director at Axis Capital Holdings Limited (AXS) returned last week to add further to his stake. The more than 1.12 million shares of this insurer indirectly scooped up, at prices ranging from $45.24 to $46.00, totaled about $51.40 million. This director has been buying shares since mid-June.

J & J Snack Foods Corp. (JJSF) saw CEO Gerald Shreiber add shares to his stake. At prices ranging from $131.52 to $129.52 apiece, the 100,000 shares indirectly acquired cost him more than $18.40 million. Note that the transactions were listed as "for estate planning purposes only."

Xerox Holdings Corp. (XRX) saw 10% owner Carl Icahn add to his stake again. He indirectly acquired almost 726,000 more shares for $17.11 to $17.20 each. That totaled almost $13.15 million. Note that Icahn purchased about 1.21 million shares in the previous week.

Kodiak Sciences Inc. (KOD) had a 10% owner indirectly pick up over 203,400 shares of this California-based clinical-stage bio-pharmaceutical company last week. At prices ranging from $46.15 to $49.29 per share, that came to more than $9.81 million.

An Avis Budget Group Inc. (CAR) beneficial owner stepped up to the buy window last week. The more than 143,100 shares of this car rental giant were priced at $30.79 to $32.85 each. That totaled over $7.66 million and brought the stake up to more than 16.93 million shares.

The chief executive officer at Red Rock Resorts Inc. (RRR), Frank Fertitta, and another director bought via trust 455,400 shares altogether of this casino operator at $15.45 to $16.60 apiece. That totaled nearly $7.41 million. Both of them purchased some shares in the previous week, too.

Executive Chair Richard Kinder paid $14.01 to $14.15 each for more than 373,200 Kinder Morgan Inc. (KMI) shares. The total for the transactions came to almost $5.26 million. Note that Kinder was a frequent buyer late last year, until mid-March. He bought 300,000 shares in July, too.

And Biglari Holdings Inc. (BH) saw its CEO, Sardar Biglari, return to the buy window. He added more than 13,800 shares of this parent of Maxim and Steak n Shake. At prices ranging from $93.50 to $97.00 per share, that totaled more than $1.31 million. He bought more than 6,500 shares in the prior week as well.