NEW YORK (Reuters) - Workers at many of the largest U.S. tech companies overwhelmingly back Democratic presidential candidate Kamala Harris, according to donation data, even as some of the most powerful tech billionaires have thrown their support to Republican rival Donald Trump.

Workers at Alphabet, Amazon ( AMZN ) and Microsoft ( MSFT ) are donating millions of dollars to the Harris campaign, significantly more than employees who are opting to send money to former President Trump's camp, according to the data compiled by political watchdog OpenSecrets. The data includes donations made by company employees, owners, and workers' and owners' immediate family members.

However, tech billionaires like Tesla Chief Executive Elon Musk and venture capital firm Andreessen Horowitz co-founders Marc Andreessen and Ben Horowitz are rallying behind Trump, citing the former president's stances on the economy, taxes and big business.

The Nov. 5 presidential election has riven Silicon Valley, once a bastion of democratic and liberal support. Venture capitalist Reid Hoffman from Greylock and entrepreneur Mark Cuban are pledging support for Harris' White House bid, with hopes of seeing more abortion rights for workers and pro-tech policies.

But in recent years several other tech leaders have bristled at Democratic President Joe Biden's business policies, including a broad attack on mergers and acquisitions and clamping down on data privacy.

Companies themselves can not directly donate to federal campaigns, including presidential ones, according to campaign finance laws. Corporations often donate to congressional and state-level campaigns through political action committees, which are funded by employee donations and limited on how much candidates can receive.

"Many businesses serve customers on both sides of the political aisle, and they don't want to alienate customers by making contributions that support just one party or one candidate in a partisan race," said Michael Beckel, research director at campaign finance reform nonprofit Issue One. While corporations are blocked from sending money directly to presidential candidates, their employees aren't, and tech employees are overwhelmingly giving to Harris.

Employees at Alphabet and its subsidiaries, which includes Google, and their family members have donated $2.16 million so far to Harris' campaign, nearly 40 times as much as Trump has received, according to OpenSecrets.

Amazon ( AMZN ) and Microsoft ( MSFT ) employees and family members donated $1 million and $1.1 million, respectively. Trump's campaign pulled in $116,000 from Amazon ( AMZN ) workers and $88,000 from Microsoft ( MSFT ) workers, as well as their family members.

Employees at Amazon ( AMZN ), which is also a top U.S. retailer and the second largest employer in the country, are outpacing donations from other e-commerce and brick-and-mortar retail workers.

For example, Walmart ( WMT ) workers have donated a total of $275,000 to both Harris and Trump, with both presidential candidates receiving nearly the same amount in funding. Trump's campaign is taking in $144,000 from Walmart ( WMT ) workers, about $14,000 more than Harris'.

Campaign donations mostly come from corporate employees who have more disposable income than the typical warehouse worker or cashier, said Sarah Bryner, director of research and strategy for OpenSecrets. Bryner said Amazon ( AMZN ) and other tech company corporate employees often make more money than those at Walmart ( WMT ), giving them more leeway to contribute to political campaigns.

Amazon ( AMZN ) corporate employees on average make more money than Walmart ( WMT ) corporate employees, who are often based in Bentonville, Arkansas. Amazon's ( AMZN ) U.S. corporate employees take home an average of $133,000 per year, while Walmart's ( WMT ) corporate workers' average annual salary is $85,000, according to data from job marketplace ZipRecruiter.

Workers and family members at Meta and Apple ( AAPL ) haven't hit the $1 million mark in donations to Harris yet, but they are continuing the trend of outpacing contributions to Trump. Meta employees have donated $25,000 to Trump compared with $835,000 to Harris, while Apple ( AAPL ) employees donated $44,000 to Trump compared with $861,000 to Harris.

Silicon Valley has traditionally been seen as more left-leaning in the U.S. In August, more than 100 venture capitalists said in a letter they would support Harris, who has been considered pro-innovation on business and technology.