Dhaka, April 9 -- A global minimum corporate tax rate could deal a major blow to the multinationals which some governments allege shift billions of dollars in profits every year to low-tax havens, as well as triggering a fundamental reassessment of corporate earnings.

The chances of such reform rose this week as Treasury Secretary Janet Yellen threw the weight of the US government behind a push to upend international tax rules.

Yet stock markets held near record highs, boosted by the near-zero US interest rates as well as a bet that a proposed 21 per cent minimum tax rate, regardless of where companies make their sales, would not be implemented for years.

But some such as Grace Peters, investment strategist at J.P. Morgan Private Bank,...