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 stock market continued its holiday-inspired rally on Wednesday, with the Dow and the S&P 500 both rising to new record highs once again. Positive readings on the Conference Board's Leading Economic Index set the tone for investors, as hopes for a stronger economy in 2014 helped support stocks even at valuations that some see as increasingly lofty. Hewlett-Packard (HPQ 0.11%), AeroVironment (AVAV -1.49%), and Boyd Gaming (BYD -1.10%) all posted much more dramatic upward moves. Let's take a closer look at all three stocks to see why they soared today.

Hewlett-Packard jumped 9% after reporting better-than-expected revenue and earnings last night in its quarterly report. Even though sales fell 3% year-over-year, producing a net-income drop of 13%, investors celebrated the fact that HP didn't produce similar disappointing results to what so many major tech companies posted in their third-quarter reports. HP still has a long way to go toward its restructuring efforts, but shareholders continue to be willing to give the tech giant the time to get itself in stronger shape going forward.

AeroVironment gained 11%, with a similar quarterly report story to HP's. The defense-oriented maker of unmanned aircraft reported 19% lower sales for the quarter, resulting in an 80% plunge in net income. But AeroVironment's order backlog more than doubled over the past six months, reassuring investors that the company's defense exposure won't necessarily hurt its prospects in the long run.

Boyd Gaming rose 10%, adding to its 4% gain yesterday after the casino company said that its Borgata casino in Atlantic City had received authorization from New Jersey gaming officials to begin operating an online-gaming site. Investors have been waiting for online gaming for a long time, and while competition in the industry is likely to be extensive, Boyd has a solid partnership with the company behind the once massively popular Party Poker site that could help it stand out from its peers.