HSBC Is Under Attack From China Upstart It Put on the Map

For years, HSBC Holdings Plc and Ping An Insurance Group Co. enjoyed a cozy relationship, from the turns they took financially backing each other to the easy rapport between their influential chairmen.

That’s why shock rippled through the top ranks of the $3 trillion British bank when it emerged the firm’s biggest shareholder was pushing for the most dramatic split in banking history.

Ping An, led by Peter Ma, is urging HSBC Chairman Mark Tucker to consider options including breaking the firm apart and listing its Asian operations separately on the stock market. In a recent private memo, the ...