AstraZeneca Plc’s shares rose after a report that Chief Executive Officer Pascal Soriot wants to move the British drugmaker’s stock listing to the US, in what would be a major blow to the UK’s equity markets.

U.S.-listed shares of AstraZeneca rose 2.5% on Tuesday.

Soriot has also discussed moving AstraZeneca’s domicile, the Times said, citing people familiar with the matter it didn’t identify. The executive is frustrated with the UK’s regulatory regime for drugs and is concerned the country is falling behind the US and China, it said.

“We do not comment on speculation,” AstraZeneca spokesman Tony Ho Wan Loke said by email.

AstraZeneca shares rose as much as 3.2% in London after the report, almost erasing their year-to-date decline. With a market value of about £160 billion ($220 billion), the drugmaker is Britain’s largest publicly traded company.

A series of companies have moved their primary stock listing from London to the US in recent years often in search of improved liquidity. International payments firm Wise Plc is the latest company to weigh such a move, saying last month that it will consult shareholders on the matter.