Ben Horowitz said he and his wife, Felicia, will make a 'significant donation' to Vice President Kamala Harris after previously supporting Donald Trump in this year's election. Gregg DeGuire/Getty Images

Billionaire venture capitalist Ben Horowitz, one of Donald Trump's former Silicon Valley supporters, said he has had a change of heart and that he and his wife, Felicia, will make a "significant donation" to Vice President Kamala Harris.

Horowitz endorsed the former president in July, one of a batch of tech titans like Tesla's Elon Musk and PayPal's Peter Thiel who have pledged to throw their sizable fortunes behind Trump.

But that was before President Joe Biden withdrew from the race and endorsed his vice president as his successor.

Horowitz explained his thinking Friday in an email to employees at Andreessen Horowitz, the company he co-founded, after Axios first reported on the story.

"As I mentioned before, Felicia and I have known Vice President Harris for over 10 years and she has been a great friend to both of us during that time," he said in the letter also posted on his X account.

"She's also been a friend to the firm in our early days, helping with several events at my house when we built the original Cultural Leadership Fund network," he added.

"As a result of our friendship, Felicia and I will be making a significant donation to entities who support the Harris Walz campaign," he continued.

In the letter, Horowitz criticized Biden for being "exceptionally destructive" on tech policies, especially on Cyrpto, Blockchain and AI.

"Although I have had several conversations with Vice President Harris and her team on their likely tech policies and am encouraged by my belief in her, they have not yet stated what their tech policy will be, so the firm will not be updating its position in that regard," Horowitz said.

He ended the email saying he is "hopeful that the Harris Administration will be much better."