Corporate executives often talk about the need for boardroom diversity, but few do much about it. Women still hold slightly less than 20 percent of public corporate board seats. African-Americans hold less than 9 percent, Asians even less, about 5 percent, and Hispanics only about 4 percent.

On Wednesday, Starbucks, the coffee giant, plans to announce it is adding three new directors to its board and in doing so will create what will be among the nation’s most diverse corporate boards.

The new directors, who will require shareholder approval, will be Rosalind Brewer, an African-American woman who is president and chief executive of Sam’s Club and vice president of Walmart Stores; Satya Nadella, an Indian-American who is chief executive of Microsoft Corporation; and Jorgen Vig Knudstorp, the Denmark-born executive chairman of the Lego Brand Group.

With the additions, the Starbuck’s board would grow to 14 people; would be 29 percent female and 36 percent ethnic minority; and would include a range of ages from millennials to baby boomers.