Constance Lau, who will become Hawaiian Electric Industries Inc.'s chief executive officer in May, will step down from her post as trustee of the Kamehameha Schools.

Citing time constraints, Lau informed the Kamehameha Schools that she intends to leave its five-member board once a replacement is found.

Lau has served as a Kamehameha trustee since 1999, and her five-year term expires in 2008. The school is funded by a $7 billion trust.

"Amidst all the excitement and the amazement that I will now have the opportunity to lead Hawai'i's largest corporation, I am incredibly saddened by the thought of leaving Kamehameha Schools, and in my heart, I never will," Lau said in an e-mail distributed to Kamehameha Schools staffers.

"I am so proud of what we have accomplished, and am privileged to be a part of Ke Ali'i Pauahi's legacy and of Kamehameha Schools and its mission."

Lau was paid about $100,000 per year for serving as a Kamehameha trustee. According to Kamehameha Schools tax filings, Lau received $113,500 during the fiscal year ending June 30, 2004.

Lau, 53, was named to succeed Robert Clarke as HEI's CEO when Clarke retires in May.

She will become the first woman chief executive of a major Hawai'i public-traded company and will be one of 20 female chief executives running a Fortune 1000 company.

With more than $2 billion in annual revenue, HEI is the largest publicly traded company in Hawai'i. Fortune magazine ranks it as the nation's 777th-largest public corporation.

The search for Lau's replacement at the Kamehameha Schools could take several months.

Probate Judge Colleen Hirai must first appoint a special trustee selection committee, which would recommend a list of candidates. Hirai would then choose Lau's replacement from those.

Lau has served with the Kamehameha Schools since 1999 when then-Probate Judge Kevin Chang named her as one of five interim trustees to replace ousted board members Henry Peters, Lokelani Lindsey, Gerard Jervis, Richard "Dickie" Wong and Oswald Stender.

The 1999 board removal came after the Internal Revenue Service threatened to revoke the Kamehameha Schools' nonprofit status for alleged tax violations and breaches of fiduciary duties.

"She has been a fantastic and collaborative team member and I speak for all of us when I say that Connie's impact on Kamehameha Schools will be felt and appreciated for decades to come," said retired Adm. Robert Kihune, chairman of Kamehameha Schools' board.

Reach Rick Daysog at rdaysog@honoluluadvertiser.com.