Despite a 3.3% gain in UnitedHealth Group Incorporated's (NYSE:UNH) stock price this week, shareholders shouldn't let up. Although prices were relatively low, insiders chose to sell US$37m worth of stock in the past 12 months. This could be a sign of impending weakness.

Although we don't think shareholders should simply follow insider transactions, logic dictates you should pay some attention to whether insiders are buying or selling shares.

Check out our latest analysis for UnitedHealth Group

UnitedHealth Group Insider Transactions Over The Last Year

In the last twelve months, the biggest single sale by an insider was when the President & COO, Dirk McMahon, sold US$8.0m worth of shares at a price of US$543 per share. That means that even when the share price was slightly below the current price of US$551, an insider wanted to cash in some shares. When an insider sells below the current price, it suggests that they considered that lower price to be fair. That makes us wonder what they think of the (higher) recent valuation. However, while insider selling is sometimes discouraging, it's only a weak signal. We note that the biggest single sale was only 16% of Dirk McMahon's holding.

Over the last year, we can see that insiders have bought 2.24k shares worth US$1.0m. But insiders sold 74.33k shares worth US$37m. In total, UnitedHealth Group insiders sold more than they bought over the last year. The chart below shows insider transactions (by companies and individuals) over the last year. If you want to know exactly who sold, for how much, and when, simply click on the graph below!

I will like UnitedHealth Group better if I see some big insider buys. While we wait, check out this free list of growing companies with considerable, recent, insider buying.

UnitedHealth Group Insiders Are Selling The Stock

The last quarter saw substantial insider selling of UnitedHealth Group shares. In total, insiders dumped US$8.2m worth of shares in that time, and we didn't record any purchases whatsoever. Overall this makes us a bit cautious, but it's not the be all and end all.

Insider Ownership

I like to look at how many shares insiders own in a company, to help inform my view of how aligned they are with insiders. We usually like to see fairly high levels of insider ownership. UnitedHealth Group insiders own 0.3% of the company, currently worth about US$1.8b based on the recent share price. I like to see this level of insider ownership, because it increases the chances that management are thinking about the best interests of shareholders.