Incidents like these underscore the need for greater shareholder rights and protections, said Reuben Edelson, a proxy adviser at shareholder-advice firm Glass Lewis & Co. LLC in Limerick, Ireland.

“I think people look to London as a stable market to invest in, and then you have incidents that flip these things upside down,” he said.

More recently, mining group Bumi Plc was rocked by a dispute between Indonesia’s billionaire Bakrie family and co- founder Nat Rothschild. The scion of the Rothschild banking dynasty had tried to take control of Bumi’s board from the Bakries, who own 30 percent of Bumi, amid a probe of alleged financial irregularities.

Ensure Autonomy

The governance measures are expected to be finalized by the U.K.’s new Financial Conduct Authority as soon as next month. They may require that independent directors constitute a majority of the board at companies with a “controlling shareholder” -- defined as holding at least 30 percent of stock. To ensure autonomy, an independent director’s appointment would need approvals in separate votes from minority shareholders as well as all investors.

Another provision could reinstate a rule, dropped in 2005 by what was then known as the Financial Services Authority, that bars controlling shareholders from influencing the day-to-day running of a company. The new measures would apply to both new issuers and listed companies.

“The move to tighten listing requirements in London can be linked to companies which, although public, continue to act as private,” said Mariyam Zhumadil, an analyst at investment bank Halyk Finance JSC in Almaty, Kazakhstan.

In a statement releasing its proposals before the FCA took over financial regulation, the FSA wrote that while reforms are “necessary at this time,” the measures should not be so stringent as to deter new IPO listings.

Blunt Tool

It proposed, for instance, to keep unchanged, at 25 percent, the minimum portion of shares that an IPO candidate must have openly traded and to cap any exceptions to the rule at 20 percent. Activist investors were seeking at least a 50 percent minimum free float as a bulwark against dominant shareholders. Such a “blunt tool” could “only be effective at the cost of damaging London’s attractiveness to issuers,” the FSA wrote.