Hawaiian Electric Industries Inc. failed to get the necessary 75 percent approval from shareholders for its sale to NextEra Energy, Inc. on Tuesday and has extended the deadline for shareholders to vote until June 10.

NextEra offered to buy HEI in December for $4.3 billion. To proceed the deal needs 75 percent approval from HEI shareholders and approval from the Hawaii Public Utilities Commission.

HEI held a shareholders’ meeting Tuesday to vote on the sale but failed to get the required 75 percent.

The company said about 23.7 million shares, representing approximately 22 percent of HEI’s total shares outstanding, remain unvoted. The company said it has “yes” votes representing about 70 percent of outstanding shares. It is hoping by extending the vote deadline that it can get enough votes to pass the 75 percent threshold.

While publicly-held companies commonly may proceed with a merger with the affirmative vote of a majority of their outstanding shares, HEI is required under Hawaii law to obtain supermajority approval from 75 percent of its outstanding shares.

The company said 90 percent of the shares that have been voted, voted in favor of the sale.