March 6 (Reuters) - Robinhood debuted its flagship $658.4 million venture fund on the New York Stock Exchange on Friday, offering retail investors a rare chance to invest in high-profile, privately held technology companies.

Private company investments have long been the playground of Silicon Valley's biggest venture capital firms, with retail investors largely shut out of the booming market where valuations have surged in recent years.

The fund, which began trading under the ticker 'RVI', has investments in prominent private companies, including software startup Databricks, fintech Ramp and financial services firm Revolut.

"There is a big gap in the market where the retail customer cannot access private assets," Robinhood CFO Shiv Verma told Reuters in an interview.

Some private companies now command valuations that rival or exceed the market capitalization of companies in the S&P 500. Databricks raised capital at a $134 billion valuation in February, while Ramp was valued at $32 billion in November.

The fund carries risks, including fluctuations in private company valuations, though these are not unique to it, analysts say. The broader venture capital exit market has also been turbulent in recent years as IPO activity slowed.

Robinhood priced the IPO at $25 per share and sold 12.6 million shares, raising less than initially targeted. Investor appetite for IPOs remains uneven as markets stay volatile amid geopolitical turmoil and fears of AI-driven disruption.

Verma said Robinhood purposely chose industry-leading late-stage companies that are "much less risky" than early-stage startups.

"These are great investments, they're going to do well and if there's some short-term volatility in the interim, because it's a closed-end fund, you're not forced to sell," he said.

Verma added the fund, which could eventually expand into other sectors including energy, robotics, aerospace and defense, also drew demand from institutional investors during the IPO roadshow.

Once known mainly as a trading app for mom-and-pop investors, Robinhood has since expanded into a broader financial services platform, helping push its market capitalization above $72 billion.