NEW YORK, Oct. 8, 2025 — Spencer Stuart, one of the world's leading executive search and leadership advisory firms, today released its 40th annual U.S. Board Index, revealing that while board composition continues to evolve, the pace of refreshment has slowed, and boards are prioritizing seasoned expertise amid a more complex operating environment.
The 2025 U.S. Spencer Stuart Board Index — a milestone edition marking four decades of governance insight – analyzes the composition, governance practices, and refreshment trends across S&P 500 boards. This year's findings reflect a landscape defined by low turnover, a shift toward proven executive experience, and a recalibration of board diversity metrics. S&P 500 boards appointed 374 new independent directors in 2025, an 8% decrease from last year and the lowest number since 2016.
"For four decades, the U.S. Spencer Stuart Board Index has tracked the steady evolution of corporate governance," said Julie Hembrock Daum, chair of the North American Board Advisory Practice. "Boards have transformed from compliance-focused bodies to strategically engaged stewards guiding long-term value. This 40-year milestone is a reminder of how far boards have come — and how essential they remain to the strength, resilience, and success of companies."
Top findings include:
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Board refreshment slowed: Only 50% of S&P 500 boards appointed a new independent director this year (down from 58% in 2024), with average turnover at 0.8 new directors per board.
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Director profiles shifting: New appointees skew older (average age 59.1) and more experienced, with 59% retired executives and continued emphasis on CEOs (30%) and financial experts (29%).
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Diversity metrics shifting: Overall, 50% of all S&P 500 directors identify as women and/or from an underrepresented racial or ethnic group - unchanged from 2024. However, the share of new appointments from these populations declined to 46% (from 59%), with women representing 38% of new directors and directors from an underrepresented racial or ethnic group 17%. Nearly all boards (99%) include at least one director from an underrepresented racial or ethnic group, 35% of all directors are women, and 58% of boards use Rooney Rule-type policies.
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Evolving board leadership: 61% of boards now separate the chair and CEO roles (up from 48% in 2015), while independent chairs have risen to 41% (from 29%).
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Greater evaluation and disclosure: 99% of boards conduct evaluations, and 80% now disclose a director skills matrix – more than double the share five years ago.
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Director compensation rising: Average pay increased 3% to $336,352, keeping pace with inflation. Compensation mix: 59% stock awards, 36% cash. Independent chair premiums average $172,867, with lead/presiding directors at $51,011.
"In today's environment of disruption and scrutiny, refreshment and succession can't be treated as check-the-box exercises," said Rebecca Thornton, co-leader of Spencer Stuart's North American Board Advisory Practice. "With turnover at historic lows, every appointment is an opportunity to shape the board's ability to guide strategy, challenge assumptions, and drive long-term value. The most effective boards are balancing the need for seasoned judgment with new skills and perspectives that reflect the realities of modern business."
Amid rising pressure from investors, regulators, and stakeholders, boards are being called on to do more than ever. Yet only 22% of CEOs report receiving effective board support to navigate today's challenges.
"What ultimately sets effective boards apart isn't just their composition, but their leadership, relationships, and culture," said George Anderson, co-leader of Spencer Stuart's North American Board Advisory Practice. "Independent leaders, strong dynamics, and a culture of engaged stewardship will define the next chapter of board effectiveness."
The U.S. Spencer Stuart Board Index reflects data through April 30, 2025, providing the most up-to-date analysis of S&P 500 governance practices available in the market. Findings are based on our analysis of the latest proxy statements from the S&P 500 filed between May 1, 2024, and April 30, 2025.