The Nasdaq logo is seen at the Nasdaq Market in New York City, U.S., September 16, 2025. REUTERS/Brendan McDermid

By Ateev Bhandari and Anuj T

(Reuters) -BillionToOne was valued at $4.4 billion on Thursday, after the molecular diagnostics firm's shares jumped 66.67% in their Nasdaq debut on Thursday, becoming the latest company to tap U.S. bourses amid a government shutdown.

IPOs have made a striking comeback as AI exuberance and falling interest rates anchor equity markets to all-time highs, fueling investor confidence in new issuers after President Donald Trump's tariffs roiled global markets in April.

While a prolonged gridlock in Washington has curbed the Securities and Exchange Commission's abilities to review filings, the agency has eased listing restrictions to allow companies to tap public markets even as the shutdown continues.

The Menlo Park, California-based company's stock opened at $100 apiece, versus the $60 offer price. Shares touched $123.45 earlier in the session and were last up 98.8% at $119.3.

It had sold 4.55 million shares above its marketed range of $49 to $55 apiece to raise $273 million in an upsized IPO on Wednesday, reflecting robust investor demand for high-growth biotech companies.

"Within the confines of the government shutdown, you can only upsize it 20%, so we took it up 20% just to give our long term public investors enough to start their positions," BillionToOne co-founder and CEO Oguzhan Atay told Reuters in an interview.

A slew of medical firms have gone public on U.S. exchanges this year. Peer Caris Life Sciences went public in New York in June, with shares trading more than 39% above issue price as of last close. BillionToOne is a molecular diagnostics company that develops non-invasive prenatal and oncology blood tests using its single-molecule sequencing technology. The company's revenue rose nearly 82% during the six months ended June 30 from a year earlier, with gross profit more than doubling over the same period.

(Reporting by Ateev Bhandari and Anuj T in Bengaluru; Editing by Shreya Biswas and Tasim Zahid)