Stocks continued to move higher as investors prepared for the Independence Day holiday. Enthusiasm about rebounding employment numbers helped to set a positive tone on Wall Street. As of 12:30 p.m. EDT, the Dow Jones Industrial Average (^DJI 0.01%) was up 104 points to 34,738. The S&P 500 (^GSPC 0.70%) gained 20 points to a new record of 4,340, while the Nasdaq Composite (^IXIC 1.10%) saw gains of 71 points to 14,594.

When it comes to stock markets, the biggest companies have a huge influence. That's why on Friday, if you want to understand the market's overall gains, you have to look at the 1% to 2% rises in tech behemoths Apple (AAPL 1.66%), Microsoft (MSFT 0.74%), and Alphabet (GOOGL 0.83%) (GOOG 0.72%). Below, we'll take a look at some of the factors helping these stocks out.

Trying to catch up 

Apple's gains of 1.5% today were quite welcome. The iPhone maker's stock has actually lagged the broader market pretty badly in 2021, with gains of just 5% year to date.

After big gains in 2020, Apple left some investors wondering what will come next to keep generating hype for the electronic device maker. The company has done an exceptional job of adding incremental functionality to its iPhones to keep them popular as long as possible, with a big focus of its recent developer conference being the latest upgrades to its long-standing operating system, iOS. By incorporating as many performance features as possible, Apple hopes to keep users inside its ecosystem rather than defecting to other providers.

For shareholders, a lot of Apple's appeal comes from its consistent stock buyback activity. Repurchases help reduce outstanding share counts, giving a boost to earnings per share figures. As long as that continues, Apple should enjoy favorable longer-term trends in its stock price.

Three people working in a server room.

Image source: Getty Images.

Soft no longer

Microsoft's 1.8% rise adds to performance that's a lot more impressive. The software giant is up 24% so far in 2021.

Microsoft generated a lot of attention recently as its market capitalization pushed above the $2 trillion mark. Although some believe that could limit the company's future upside, Microsoft is working on plenty of innovative new projects to sustain its upward momentum. For instance, the Azure cloud infrastructure platform has become the second-biggest player in the fast-growing cloud market. Microsoft has successfully transitioned to more of a recurring revenue model, largely giving up on perpetual licenses in favor of subscriptions that eliminate the need to persuade users to upgrade their software on a regular basis.

Now, investors are looking at the coming Windows 11 operating system as well as ongoing advances in video gaming and augmented reality as new growth opportunities. Microsoft has plenty of room to keep rising.

No longer searching for big gains

Finally, Alphabet's nearly 2% move higher adds to its already impressive gains for the year. The search giant is up 42% year to date.

Alphabet struggled for a long time to keep up with Apple, Microsoft, and other tech companies. Although its stranglehold on internet search remains unchallenged, Alphabet found itself playing catch-up in some key areas.

Now, though, Alphabet is making maximum use of its assets. Its Google Cloud business is growing rapidly, while the company has tapped into the full potential of its YouTube video service. A host of other ancillary businesses are showing good prospects of their own, offering some optionality beyond Alphabet's core areas. On the whole, strong momentum for Alphabet seems to be building, and that could keep the stock moving higher for a while.

Don't ignore the obvious

It doesn't take much courage to own the biggest tech stocks in the market. Yet what's surprising is how much potential these three companies still have to grow. That makes them promising investments.