Insider buying can be an encouraging signal for potential investors, especially when markets are near all-time highs. The week's most notable insider buys were at a health insurer, an oil exploration and production company, and a biotech. Some insiders were making return trips to the buy window.

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.

Note that with earnings-reporting season over, many insiders are free once more to buy or sell shares. Here are a few of the most noteworthy insider purchases that were reported in the past week.

Oscar Health

Health insurance provider Oscar Health Inc (OSCR) saw co-founder Joshua Kushner purchase more than 1.21 million shares and CEO Mario Schlosser add 57,300 shares in the past week. At per-share purchase prices ranging from $16.18 to $18.50, that added up to almost $22.62 million altogether. Kushner, who is also vice chair and a 10% owner, saw his stake lifted to more than 4.75 million shares by his purchases.

The New York-based company went public back in March, and the stock traded as high as $37 per share shortly after the initial public offering. It is down over 43% since then, ending Friday at $17.50 a share, within the purchase price range above. The consensus price target is $24.17, and analysts on average recommend buying shares.

Continental Resources

In the middle of last week, a director at Continental Resources, Inc. (CLR) returned to add to a stake. At $40.87 to $42.60 apiece, the more than 261,700 shares purchased cost that director nearly $10.99 million. This acquisition increased the director's stake to more than 13.69 million shares. That means the director is also a beneficial owner.

The Oklahoma City-based exploration and production company saw its shares receive a target price bump by Keybanc last week. The share price was at $41.97 as Friday's regular trading ended, which was a gain of about 9% for the week but still within the director's purchase price range. The stock has overrun its $40.45 consensus price target, but analysts overall recommend buying shares.

Kodiak Sciences

A beneficial owner of Kodiak Sciences Inc (KOD) returned to the buy window last week. At $93.81 to $94.73 per share, the more than 31,800 shares most recently acquired totaled around $3.00 million. That owner also bought more than $5 million worth of shares earlier this month and was adding shares throughout August, as well. The stake was listed as up to more than 13.3 million shares, compared to more than 51 million shares outstanding.

The Palo Alto, California-based clinical stage biopharmaceutical company announced a performance incentive plan for executives earlier this month. The stock is up about 9% since then, including more than 6% in the past week, and was last seen trading at around $102.75. That is more than 8% higher than the top of the owner's latest purchase price range. The consensus price target is $121.55, and the consensus recommendation is to buy shares.

And Others

Some other sizable insider purchases from last week include:

• Cricut Inc (CRCT) beneficial owner bought nearly 533,000 shares for almost $16.5 million.
• Sensient Technologies Corporation (SXT) beneficial owner bought nearly 88,000 shares for over $8.0 million.
• Rain Therapeutics Inc (RAIN) beneficial owner bought over 392,000 shares for almost $6.5 million.
• Western Alliance Bancorporation (WAL) executive board chair bought 200,000 shares for $5.0 million.
• Designer Brands Inc (DBI) executive board chair bought more than 178,000 shares for over $2.2 million.
• Asana Inc (ASAN) CEO bought almost 14,000 shares for about $1.4 million.

Note that some smaller amount of insider buying at 1847 Goedeker (GOED), Enterprise Products Partners (EPD), FireEye (FEYE), Gannett (GCI), Opko Health (OPK), and ZoomInfo (ZI) was reported in the past week, as well.