Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrials (^DJI -0.12%) passed another milestone today in its attempt to recover from its January losses, climbing back above the 16,000 mark with a gain of almost 64 points. Without any obvious far-reaching rationale for the gains, investors found hot stories across all of the Dow's sectors, as AT&T (T 0.19%) and UnitedHealth (UNH 2.15%) outpaced the Dow on a percentage basis. Nike (NKE 1.55%) and Boeing (BA -0.20%) also rose more than 1%, showing the breadth of the advance.

AT&T's 1.7% gain came apparently at the expense of rival Verizon, which announced a change in the pricing structure with its "More Everything" plan. With Verizon making most of its savings contingent on customers choosing its Edge plan, the value of the plan isn't as apparent as some of the changes that AT&T and other rivals have made to their offerings. If AT&T can actually win a price-war against Verizon, it could potentially threaten Verizon's No. 1 position in the U.S. wireless market -- all the while paying investors the best dividend yield in the Dow Jones Industrial Average.

For UnitedHealth, news that enrollment under plans in the Affordable Care Act had risen in January might have played a key role in pushing shares up about 1.4%. UnitedHealth rival WellPoint said that the figures were consistent with its expectations, and its shares saw similar gains to those of UnitedHealth. Still, there's a lot uncertainty remaining about how Obamacare's rollout will fare as the key March 31 deadline approaches, and so the jury's still out on whether UnitedHealth's more conservative approach to the health-insurance exchanges will prove better than WellPoint's more aggressive exchange strategy.

Meanwhile, Nike's and Boeing's respective gains largely seem to reflect their underlying fundamental strength. For Nike, brand awareness has been a key component of its fight against up-and-coming rivals in the athletic apparel and footwear industry. With such a strong lineup of endorsement talent behind its products, Nike would have to misstep badly in order to give up its head start, but it also can't afford to stop innovating. Similarly, Boeing has a huge opportunity with trillions of dollars of potential future sales in the balance, and its efforts to boost efficient production of all the aircraft its customers have already ordered could well bear fruit for years, if not decades, to come. Doing so, though, requires enough discipline to avoid what could be costly mistakes if things go wrong.

Dow 16,000 is a reality once more, but some investors still wonder whether it will last. For now, though, most investors appear convinced that the correction is over and that it's back to the normal full-speed-ahead mode that we've seen for years.