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Rail-Splitter Capital Management
Curtis Macnguyen runs Rail-Splitter Capital, a concentrated growth equity manager in Chicago with an estimated $500M–$1B under management.
Rail-Splitter Capital Management
RAIL-SPLITTER CAPITAL MANAGEMENT LLC is an SEC-registered investment adviser in WINNETKA, IL, registered since 2026. The firm employs 3 employees and 3 investment advisers. It is based in WINNETKA, IL.
General information
Firm type
Asset Manager
Year founded
2006
AUM
$500M – $1B (Altss estimate)
Location
Region
North America
Country
United States
City
Winnetka
Corporate office
Chicago, IL, United States
Principals
Curtis A. Macnguyen
CEO and Managing Partner
John J. Filosa
Managing Partner
Sector focus
Frequently asked questions
Who runs investment decisions at Rail-Splitter Capital?
Curtis Macnguyen, the CEO and Managing Partner, acts as lead portfolio manager and makes all final investment decisions. John Filosa, the firm's other Managing Partner, oversees research and risk. The two founded the firm together in 2006 and remain the sole owners.
Does Rail-Splitter participate in private investments, or is it strictly public equities?
Rail-Splitter is exclusively a public-equity manager. It does not invest in venture capital, private equity, or private credit. The firm has run the same concentrated all-cap growth strategy since 2006 without expanding into alternative asset classes.
How concentrated is the portfolio?
Rail-Splitter typically holds between 25 and 35 names. The firm targets durable revenue growth and structural change across technology, consumer, healthcare, and business services. It avoids broad diversification in favor of high-conviction positions built on deep fundamental research, management interviews, and primary sourcing.
What is Rail-Splitter's capacity, and does it plan to close to new capital?
The firm has a hard capacity ceiling because it refuses to dilute its concentrated all-cap strategy by launching additional products. While it has not publicly disclosed a specific closure threshold, the firm's historical posture suggests it would close to new investors well before reaching the multi-billion-dollar AUM levels that most growth boutiques pursue.
Is Rail-Splitter related to any other investment firm or family office?
No. Rail-Splitter is an independent, employee-owned partnership with no parent entity. The firm was created when founders Curtis Macnguyen and John Filosa left Northern Trust's institutional asset management group in 2006 to build their own concentrated growth equity franchise.
Profile maintained by Altss using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.
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