With just a quarter left to go in 2013, the stock market continues to post impressive gains for the year. Overall, the Dow Jones Industrials (DJINDICES:^DJI) have risen more than 15% so far this year, and that doesn't even include the impact of dividend payments from the Dow's various components.

But even in a wide-ranging bull market that has lifted all but two of the Dow's current members, some companies stand out from the crowd. Let's look at the Dow's best performers during the first nine months of 2013.

Boeing (NYSE:BA), up 58%
Boeing has flown much higher than any other current Dow component so far in 2013, and what's arguably most surprising about its advance is how it came in the face of adversity. Even with the company's 787 Dreamliner having been grounded for months early in 2013, investors looked past the inevitable growing pains to focus on the huge demand for the Dreamliner and Boeing's other commercial airliner offerings. With trillions in potential sales coming in over the next 20 years, Boeing simply needs to deliver what customers want without further operational hang-ups.

Nike (NYSE:NKE), up 42%
As one of the newest Dow members, Nike has quietly put up better returns in 2013 than the average's other higher-profile entrants. Last week's earnings report from the athletic-goods giant merely continued a long trend of success, as sales of training, running, and casual shoes all helped push North American segment performance higher. Even in the face of heightened competition, Nike has absorbed its fair share of a growing market for sporting goods generally. So long as those favorable trends continue, Nike is well-positioned to capitalize.

United Technologies (NYSE:UTX), up 33.7%
United Technologies has benefited from the same tailwinds that Boeing has experienced, as the company gets a huge part of its overall revenue from its Pratt & Whitney and Goodrich divisions. The acquisition of Goodrich essentially marked United Tech's doubling-down on the aerospace industry, and solid demand throughout the industry has the company's stock flying high. Even as the shutdown has raised some fears of weakness on the defense side of its business, United Tech nevertheless has the resources and determination to build up its other divisions to make up for it.

UnitedHealth (NYSE:UNH), up 33.6%
Health-insurance giant UnitedHealth has almost matched United Tech's performance, riding high on the back of positive speculation about Obamacare and its impact on the insurer. With Obamacare's health-insurance marketplace exchanges having opened earlier this week, UnitedHealth hasn't been a big player in many states' exchanges. Nevertheless, trends toward less health-care spending have helped bolster UnitedHealth's profitability, and any level of success from Obamacare can only help the company's prospects rise even further.

All four of these stocks have delivered impressive results for their shareholders. Yet they also have the potential to keep climbing as long as their respective business models continue to support the profits they've generated.

Fool contributor Dan Caplinger has no position in any stocks mentioned. The Motley Fool recommends Nike and UnitedHealth Group. The Motley Fool owns shares of Nike. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.