Donald Trump has raised $12mn at a fundraiser for top venture capitalists and entrepreneurs in San Francisco, marking the most significant sign yet that the former Republican president is making inroads in the Democratic stronghold.

Trump began a three-day West Coast charm offensive on Thursday at the sold-out event hosted by Silicon Valley investor David Sacks at his $20mn mansion on “billionaire’s row” in the city’s ritzy Pacific Heights district.

Ryan Selkis, the chief executive of cryptocurrency intelligence firm Messari, who attended the event, told the Financial Times said Trump spoke on artificial intelligence, energy and crypto and had his audience “eating out of his hands”.

“It felt like a particularly wild moment in Silicon Valley politics,” he said, adding: “The blue wall has been breached.”

The event, coming just days after Trump was found guilty on 34 counts of felony in New York last week, cost between $50,000 and $300,000 a head, according to Harmeet Dhillon, a Republican party official and lawyer whose firm represents the former president.

The fervour revealed the extent to which some luminaries of Silicon Valley, long considered a particularly liberal part of a blue state, are warming to Trump as they fret over issues such as free speech, technology regulation and taxes. The crypto sector in particular has felt aggrieved by what it sees as a hostile regulatory regime under the Joe Biden administration.

Dhillon posted on X that crypto leaders from exchange Coinbase as well as the Winklevoss twins were present at the event.

She said the ex-president was “relaxed, happy, and cracking jokes” about AI at the reception, after being introduced by Republican senator JD Vance as well as Sacks.

Jacob Helberg, a senior Palantir executive who recently announced a $1mn donation to the Trump campaign after donating to Biden in the 2020 election, was among those seen arriving at the hilltop mansion for the event. A Trump campaign spokesperson said there were more than 100 attendees.

Helberg said: “This event was proof that president Trump’s campaign is creating a generational realignment among technology founders . . . and makes him more competitive in even the most traditionally blue communities.”

He added the former president will “save AI and crypto from the Biden administration’s penchant for strangulation”.

When Trump last visited San Francisco in 2019, he was confronted by crowds of protesters. By contrast, ahead of his arrival this week a group of loud pro-Trump supporters gathered around Sack’s usually quiet residential street, chanting “USA, USA, USA” and “We want Trump”, waving American flags and facing off against several counter-protesters. 

“David Sacks hosting is significant,” said Michelle Sine, a self-employed real estate agent and resident of nearby Marin who attended the rally. “The intellectual elite and that group [who supported Trump were] almost going into witness protection four years ago. Now everyone is being more public about it.”

Sacks formally endorsed the former president on X just ahead of the event, citing his “economic policy, foreign policy, border policy, and legal fairness”, while arguing President Biden had “colluded with tech platforms to censor the internet”.

Billionaire Tesla chief executive Elon Musk responded the post was “thoughtful”.

While the entrepreneur has been vocal in his opposition to Biden, it is unclear whether he will formally endorse or donate to Trump.

Musk last week denied a report that he had been in talks with Trump over an advisory role in his administration, should the former president win in November.

The event came a week after Trump was found guilty of conspiring to buy the silence of a porn actor ahead of the 2016 election and covering his tracks in business records. The unanimous verdict enraged his longtime supporters but also prompted new endorsement and funding, including from Silicon Valley.

Within hours of the decision, Shaun Maguire, a partner at Sequoia, posted he had donated $300,000 to Trump, adding the timing “isn’t a coincidence”.

Billionaire investor and Sequoia partner Doug Leone this week took the rare step of making a public statement via X, writing he too was supporting Trump, despite renouncing his backing for the ex-president in 2021 in the wake of the Capitol riots.

“I have become increasingly concerned about the general direction of our country, the state of our broken immigration system, the ballooning deficit, and the foreign policy mis-steps, among other issues,” he wrote.

Shawn Steel, a Republican National Committee member from California, said PayPal and Palantir co-founder Peter Thiel, previously a Republican megadonor, had played a part in pro-Trump momentum by helping to build networks of young tech-savvy party members, describing him as “one of our great teachers”. “The libertarian instinct has finally emerged in the valley,” he added.

Thiel is refraining from publicly endorsing or donating to any candidate, however, said a person familiar with his thinking.

Despite the shift to the former president there remains a group of central Silicon Valley donors who support Biden and are leading a fierce pushback against Trump, including venture capitalist Vinod Khosla and Reid Hoffman, co-founder of LinkedIn.

Hoffman warned in The Economist this week that “American business should not empower a criminal”.

Trump is continuing his West Coast tour with a Los Angeles event on Friday followed by a fundraiser in Newport Beach hosted by Palmer Luckey, founder of defence group Anduril and Oculus VR.

With a US flag blowing against his face, one supporter at the rally outside Thursday’s event said: “As you can see the wind has shifted directions in San Francisco and there is a growing red wave for Trump.”