Senate Majority Leader Harry Reid of Nev. speaks with reporters following a Democratic strategy session on June, 11, 2013 © J. Scott Applewhite, AP

With Senate approval of the so-called Gang of Eight's immigration reform plan June 27, it's time to take stock of how the changes will impact one important group of companies.

The ones in your investment portfolio.

My key takeaways in some key groups and names:

Proposed immigration reform from the Senate is great news for high-tech companies such as Google (GOOG), Facebook (FB) and Microsoft (MSFT), because it will let in more high-skilled workers. These companies have long lamented shortages of these workers in the immigration pool, compared with what's available globally. Who knows? It might even mean that we see the next Google.

More immigrants, and more legalizing undocumented workers, will put downward pressure on wages for low-skilled jobs. This will benefit companies that use lots of these kinds of workers, such as restaurant chain Chipotle Mexican Grill (CMG), hotelier Marriott International (MAR) and homebuilder Lennar (LEN). It would also help ease shortages of drivers for companies like FedEx (FDX) and United Parcel Service (UPS).

Giving legal status to undocumented workers means they will spend more on things that last a long time, such as houses, cars and washing machines. That should help companies including Lennar, General Motors (GM), and Home Depot (HD).

A big part of immigration reform involves stepped-up enforcement -- and border-control measures may get tougher as the bill moves through the House. This would likely help companies such as Raytheon (RTN), United Technologies (UTX) and Halliburton (HAL).

But will anything happen?

Of course, it's no sure bet that anything like the version of immigration reform approved by the Democratically controlled Senate will see the light of day, given the polarization in Washington, D.C., and the fact that the House is controlled by Republicans.

However, because Republicans got trounced in the last presidential election -- in part because immigrants rejected their hard-line stance on immigration reform -- my guess is that something will get through the House.

Sen. Chuck Schumer, D-N.Y., has a natural bias, of course, as a big proponent of reform. But he agrees. He recently predicted that public pressure on Congress to pass immigration reform would have the House putting up something like the Senate plan for a vote within the next few months. It would be the most sweeping immigration action since the 1980s.

Given that, here's a closer look at what might change in key sectors, and how it would impact some brand-name stocks a lot of investors own.

Technology and engineering

In the emotional and polarizing debate on immigration, we often hear the warm and fuzzy -- and mostly true -- assertion that "we are a nation of immigrants." The subscript is that excluding newcomers is tantamount to excluding yourself, or your parents or grandparents.

That makes you stop and think about the importance of immigration on a personal level.

But to understand the potential economic impact immigration reform, forget all that and consider the following eye-opening observation from famed technology analyst Mary Meeker: 60% of the top 25 U.S.-based tech companies were founded by first- or second-generation immigrants.

They include Apple (AAPL), Google, IBM (IBM), Amazon.com (AMZN), Yahoo (YHOO) and Linkedin (LNKD).

Not only have all of these companies deeply changed our lives -- mostly for the better -- but they have also created 1.2 million jobs, says Meeker, who is now with the venture capital firm Kleiner Perkins Caufield & Byers. Many of these jobs pay quite well, thus they contribute to overall economic growth. (You can see the full list of tech companies founded by immigrants or their immediate offspring on page 87 of Meeker's slide show here.)

Similarly, 25% of high-tech startups in the United States from 1990 to 2005 were founded or co-founded by an immigrant, according to the National Venture Capital Association.

Immigration reform measures now moving through Congress increase the odds that more paradigm-shifting tech companies will be founded here. The Senate version substantially increases the number of high-skilled, highly educated workers who can immigrate here under H1B visas and green cards, says Greg Siskind, an immigration attorney in Memphis with Siskind Susser. The legislation also lifts country quotas, which relaxes restrictions on immigrants from India, a main source of tech workers, notes Siskind.

Even if these immigrants don't found the next Google, they will help satisfy the deep shortages of highly skilled workers in the tech sector that tech companies have complained about for years. "This is very good news for recruiting highly skilled workers," says Siskind. So it would be a big plus for tech companies like the ones mentioned above, as well as for manufacturers such as Intel (INTC), Texas Instruments (TXN), Caterpillar (CAT) and General Electric (GE), which need high-skilled workers to set up and manage plants and IT systems.

"Despite our relatively high unemployment rate, there are probably three million science and engineering jobs that have gone unfilled for over a year in the U.S.," says Oliver Pursche, author of "Immigrants: Unleashing the Economic Force at our Door" and manager of the GMG Defensive Beta (MPDAX) fund, which has beaten competing funds by 5.9% a year, annualized, over the past three years, according to Morningstar.

On the downside, new rules in the Senate version would slow down the process of granting H1B visas, hike the fees and double or triple the amount of time approval takes, says Siskind. Even worse, a House version of immigration reform rules makes no new concessions for green cards for these kinds of workers, although that could change.

Image: Michael Brush

Michael Brush

Fast food, hotels, homebuilders and farmers

There's an understandably heated and emotional debate about the impact on wages from letting more immigrants in, and from legalizing undocumented workers already here. The academic research isn't much help because it is mixed. Companies that employ the undocumented don't share much data on the subject, for obvious reasons. But here's my own take, based on interviews with several experts and on basic logic.

More immigrants, and the legalization of undocumented workers, will put downward pressure on wages for low-skilled jobs. And this will benefit companies that employ lots of low-wage, low-skilled workers, including Chipotle, McDonald's (MCD), Starwood Hotels & Resorts Worldwide (HOT), Marriott International, homebuilders including Lennar, and farming and agricultural companies, which run on low-skilled jobs.

Transport companies such as FedEx, United Parcel Service and trucker Swift Transportation (SWFT) should also benefit because they suffer from a shortage of drivers, says Fariborz Ghadar, the director of the Center for Global Business Studies at Penn State's Smeal College of Business. Legalizing undocumented workers will help these companies, because their new legal status will allow these immigrants to more easily get driver's licenses and insurance.