If you add up all the offshore cash held by S&P 500 companies, about 60 percent of it would be in technology companies, according to Bernstein analyst Toni Sacconaghi.

That means tax reform proposals in the House and Senate could benefit companies like Apple, Cisco, Microsoft and Oracle, Sacconaghi wrote in a Monday note.

The tax reform proposals currently under consideration reduce corporate tax rates domestically and free up offshore cash. While technology companies don’t have the highest tax rates domestically, many do business globally: 24 major technology companies represent foreign cash of about $550 billion, Sacconaghi said.

Tech companies that do pay domestic taxes on the high end could also be poised to win from tax reform, Sacconaghi said, pointing to companies like Visa, ADP and Texas Instruments.

But a separate research note from S&P Global Ratings earlier this month said that while large technology and healthcare companies tend to have lower tax rates, retail and transportation companies have higher tax rates.

“If you look at the tax rate for tech today as a sector, its tax rate is about 19.5 percent. The rest of the market is at 24.6 percent. So if you end up having a lower tax rate, something that’s 20 [percent] — or, on a global basis, going to be less than 20 — then tech’s simply not going to benefit as much because it’s starting from an existing lower tax rate,” Sacconaghi told CNBC’s “Fast Money: Halftime Report.”

On the other hand, companies like IBM, HP and Hewlett Packard Enterprise don’t stand to gain much on either their domestic or overseas earnings, Sacconaghi said.

“The companies that are going to benefit less are companies that have existing low tax rates and have little to no trapped offshore cash,” Sacconaghi said. “Their tax rate may not go down, it may actually go up.”

There are also some risks to technology companies in the new proposals, according to Sacconaghi. In particular, one House proposal would put a 20 percent tax on payments made to foreign affiliates, and a Senate proposal takes a softer, but similar, approach, according to Sacconaghi.

Still, the “winning” companies have told CNBC they support tax reform on the whole. Cisco said the House Ways and Means proposal would “unleash a new wave of innovation, investment, and entrepreneurship” in the U.S. Oracle declined to comment on Sacconaghi’s analysis, and other companies were not immediately available to comment.

“If you sell globally, you earn money globally. If you earn money globally you can’t bring it back into the United States unless you pay 35 percent plus your state tax,” Apple CEO Tim Cook told CNBC’s “Mad Money” in May. “And you look at this and you go, ‘this is kind of bizarre.’ You want people to use this money in the United States to invest more.”

— CNBC’s Michael Bloom and Patti Domm contributed to this report.

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