WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC — 13F Portfolio

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC (WBIM) is the dedicated asset management arm of William Blair, a privately held global financial services firm headquartered in Chicago, Illinois. WBIM operates as an SEC-registered investment adviser and institutional asset manager, overseeing a range of actively managed equity, multi-asset, and fixed income strategies for pension funds, endowments and foundations, sovereigns, financial intermediaries, and other professional investors worldwide. The firm files Form 13F with the U.S. Securities and Exchange Commission under CIK 0001644956. WBIM’s equity capabilities span U.S., global, international, and emerging markets mandates, with particular depth in high-conviction growth and quality-oriented strategies across the market-cap spectrum, including small- and mid-cap portfolios. Fixed income and multi-asset offerings emphasize active security selection, sector allocation, and risk management within well-defined guidelines. The firm’s research platform is fundamentally driven and team-based, integrating bottom-up company analysis with top-down context. The firm’s 13F reports aggregate discretionary long positions in U.S.-listed equities and certain equity-linked instruments held across its strategies. These disclosures reflect U.S. holdings within global and regional equity portfolios, as well as dedicated U.S. strategies, rather than a single commingled fund. They provide a position-level view of how WBIM’s active, growth-leaning philosophy is expressed in listed U.S. securities. Within a 13F analytics environment, the complete 13F history associated with CIK 0001644956 can be organized into quarter-end snapshots, allowing allocators to examine the evolution of WBIM’s 13F Portfolio Composition by issuer, sector, and market-cap band. Normalizing these holdings to a user-defined starting notional supports reconstruction of a notional Historical Track Record for the long-only U.S. equity sleeve implied by the filings.

William Blair Investment Management is best known for its active, research-intensive growth and GARP (growth at a reasonable price) equity strategies. The firm seeks companies with sustainable competitive advantages, attractive and durable earnings growth, strong balance sheets, and capable management teams, while maintaining discipline around valuation and downside risk. Core elements of the WBIM equity philosophy include: - Bottom-up fundamental research focused on business quality, industry structure, and long-term growth drivers. - Preference for companies with high returns on invested capital, strong cash-flow generation, and opportunities to reinvest profitably. - A multi-analyst, team-based decision process that emphasizes debate, risk assessment, and consistency across strategies. The strategy set covers U.S. small, smid, and large cap growth equities; global and international growth portfolios; emerging markets strategies; and complementary fixed income offerings. Within U.S. equities, portfolios tend to be diversified across sectors but exhibit persistent tilts toward growth-oriented industries such as technology, health care, consumer, and select industrial and business services names. Value and cyclically exposed businesses may be included when they align with the firm’s quality and growth criteria. Turnover is moderate, reflecting a multi-year investment horizon but active trading when fundamentals, valuations, or competitive dynamics change. Portfolios are typically constructed with a meaningful but risk-managed level of concentration: a limited number of high-conviction positions form the core, complemented by additional names that diversify factor and industry exposures. This yields a profile of elevated active share versus broad benchmarks. WBIM incorporates risk management at the portfolio construction stage through position sizing, sector and country limits, and ongoing monitoring of factor exposures. Environmental, social, and governance (ESG) considerations are integrated into fundamental analysis where material to business quality and risk. For observers using 13F data, the U.S.-listed sleeve visible in the filings is the expression of these active strategies within U.S. markets. A Portfolio Simulator or Backtesting Service can ingest the quarter-end holdings to run historical replication, illustrating how a notional implementation of the reported portfolios would have compounded over varying market regimes, subject to the inherent reporting lag and the absence of non-U.S. and non-equity exposures in Form 13F.

Viewed through its SEC reporting, WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC is an active, fundamentally driven asset manager with a clear growth and quality orientation across U.S. and global equity markets. The 13F record captures the U.S.-listed equity expression of that philosophy—diversified across sectors, with moderate turnover and a finite set of high-conviction positions that embody the firm’s bottom-up research views. For allocators and researchers, organizing WBIM’s filings under CIK 0001644956 into a coherent 13F History allows for detailed examination of how the firm’s 13F Portfolio Composition has evolved across sectors, capitalization tiers, and individual issuers through different market environments. A normalized reconstruction of the reported holdings supports an indicative Historical Track Record, against which one can evaluate the reconstructed capital trajectory and infer periods of positive or negative Alpha Generation vs S&P 500 for the observable sleeve. Analysis of the time-varying Volatility Profile adds further context on how the strategy’s growth and quality tilts have interacted with changing equity regimes. Because Form 13F excludes non-U.S. securities not listed in the United States, fixed income, derivatives, and cash, these analytics should be interpreted strictly as a lens on WBIM’s gross long U.S.-listed equity exposure rather than a complete representation of all mandates. Within that boundary, a central diagnostic question for allocators is how a concentrated, research-intensive, growth-tilted equity portfolio of this type is likely to respond if market leadership shifts decisively—between growth and value, quality and cyclicality, or U.S. and non-U.S. markets—over a full cycle, and whether WBIM’s historical positioning suggests structural tilts or adaptive adjustments in the face of such regime changes.

The risk profile implied by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC’s 13F disclosures is that of an active, growth-tilted, long-only equity manager with diversified sector exposure and meaningful security selection risk. At the aggregate level, a reconstructed U.S. equity portfolio based on the filings is likely to exhibit: - Equity-market beta moderately above or near 1.0, depending on the period, reflecting full participation in equity markets with a quality and growth orientation. - Factor tilts toward growth, quality, and, at times, momentum, alongside an underweight to deep value or highly leveraged cyclicals. - Concentration in a finite number of high-conviction holdings, leading to non-trivial idiosyncratic risk at the stock level, while maintaining broad diversification across industries. Because WBIM emphasizes business quality and balance-sheet strength, its portfolios may historically show some resilience relative to broad benchmarks during periods when markets reward quality and earnings durability. Conversely, in environments characterized by sharp value rallies or speculative momentum in lower-quality segments, a growth-leaning discipline can experience periods of relative underperformance even when the absolute capital trajectory remains positive. From a path-risk perspective, the reconstructed equity sleeve would be expected to experience meaningful drawdowns during major equity bear markets, in line with other active growth managers, with recovery dynamics tied to the reassertion of fundamentals and growth leadership. Diversification across sectors and regions (within the constraints of U.S.-listed holdings) and risk controls around position sizes are designed to mitigate extreme single-name shocks, but cannot fully insulate the portfolio from systemic equity stress. Using a 13F-driven analytics framework, quarter-end holdings can be connected into a normalized time series to estimate an indicative Volatility Profile for the reconstructed U.S. equity sleeve. From that same historical replication, allocators can assess the magnitude and persistence of drawdowns and summarize risk-adjusted outcomes via metrics such as an indicative Alpha Generation vs S&P 500, recognizing that such measures apply only to the public long-equity component and not to global or multi-asset sleeves managed by WBIM.