Phillip Frost Added Another 13,000 Opko Shares To His Stake

• One CEO is notably a longtime, frequent buyer of his company's shares.
• His most recent purchases included more than 13,000 shares.

For well more than a year, the CEO of Opko Health Inc. OPK frequently has bought shares of the biotech company. Conventional wisdom says that insiders and 10 percent 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.

Phillip Frost, board chair and chief executive at this Miami-based company, bought another 13,300 shares last week. The share prices ranged from $10.09 to $10.41, for a total of more than $136,000. Earlier this month, he acquired more than $653,000 worth of Opko shares. His stake has risen to more than 160.36 million shares. Opko has around 557.5 million shares outstanding.

Opko has a market capitalization near $6 billion, but doesn't offer a dividend. It's one of the most shorted Nasdaq stocks, with 21.4 percent of the float sold short. Shares have climbed more than 12 percent so far this month, closing recently at $10.83, above the CEO's latest purchase prices. The stock is up about 6 percent year-to-date.