Case study

Beyond 60/40: How Stone Temple built and manages a 50% private markets strategy using Navigator

Tim Hall, a trusted advisor with 25+ years of global investment experience, Alex Herman, a multi-asset class portfolio manager with 16+ years of experience, and David Ward, an expert in operational infrastructure with over 30 years in the field, are the co-founders of Stone Temple Partners. From the beginning, they asked a bold question: What would the best $20 billion family office in the world do? Then they set out to build it — not for one ultra-wealthy household, but for multiple families on a shared platform. These sophisticated clients all have meaningful assets, complex needs and a desire for more than a traditional 60/40 portfolio. They didn’t only want advice; they wanted an engine, a system and a clear strategy. 

Stone Temple understood their clients’ needs and carefully built their investment and wealth advisory platform around high-caliber investment professionals, deep relationships with best-in-class managers and strategically constructed portfolios with over a 50% allocation to private market investments. Even so, this strong foundation was not enough. Running unique portfolios for multiple families, each with legacy positions, custom preferences and different timelines, Stone Temple quickly encountered significant bottlenecks and limitations in managing their clients’ assets using Excel spreadsheets.

FIRM

Stone Temple 
Partners

LOCATIONSS

New York Philadelphia

FIRM TYPE

Investment Management /
Wealth Advisory

CURRENT AUM

$750 million

PRIVATE MARKETS ALLOCATION

50% or more

KEY CHALLENGES

Stone Temple managed multi-million dollar drawdowns and 10-year pacing plans through fragmented spreadsheets, where every update, capital call forecast and scenario had to be manually reconciled. Beyond the inefficiency, it left the firm without a scalable way to illustrate future portfolio outcomes for clients as they grew.

Managing portfolios with centralized control
Each family Stone Temple serves has distinct liquidity requirements and investment mandates. While each client needed tailored execution, the firm’s objective was to manage investments through a unified philosophy and shared risk framework. Maintaining this balance within disconnected planning tools proved increasingly inefficient. Alex Herman, founder and CIO, says, "The three of us are responsible in different ways for being able to look at all clients from an allocation, reporting, portfolio construction and risk management perspective… and to do that on a centralized basis."

Modeling complex private market pacing
With private investments representing more than 50% of total assets under management, Stone Temple needed a precise yet flexible way to model capital calls, distributions and liquidity timelines. Spreadsheets were not built to accommodate dynamic updates or multi-year horizon modeling.

Cash drag and client hesitation
Without clearly visualizing projected liquidity and future commitments, some families hesitated to allocate capital to alternatives at the recommended size. This resulted in persistent underallocation — often by 10–20% — and missed return opportunities. David Ward, founder and COO, explains, "Most families, even very sophisticated ones, can’t wrap their heads around committing more dollars than they have out at any one time. It’s just very hard to do that without the right tools."

Operational inefficiency and limitations to scale
Planning models required significant manual effort to update and validate. A single assumption change could lead to hours of revisions across spreadsheets, slowing down decision-making and limiting the team’s ability to scale its services.

Navigator probably drives a 150 bps pickup in returns just by fixing the private allocation drag.

Alex Herman, Founder & Cio

With Addepar Navigator, Stone Temple has experienced:

90%

reduction in 
planning time

10-20%

allocation gaps
closed

150

basis point 
return lift

RESULTS

Implementing Navigator: From concept to infrastructure

Stone Temple selected Addepar Navigator to transform their planning and execution infrastructure, replacing manual workflows with a centralized, continuously updated platform that supports forward-looking analysis and consistent decision-making.

Now the team can:

  • Model capital pacing, drawdowns and liquidity over multi-year periods

  • Apply consistent risk and return assumptions across families while preserving custom execution

  • Simulate individual private investments or construct batched models across strategies

  • Support scalable planning across each household and legal entity with transparency and precision

“Clients used to live in two static worlds, what I have today, and what it looks like fully called. Navigator lets them feel what it’s going to be like to own the portfolio over time,” says Alex Herman. Navigator became the foundation for centralized modeling, driving alignment across families and enabling more proactive planning conversations.

Forecasted asset allocations with a heat map highlighting deviations from target ranges over time

Real impact at scale

Closed 10–20% allocation gaps
Navigator helped identify underallocations in asset classes and increased capital deployment across families.

150 basis point return lift
By reducing cash drag through precise pacing, Stone Temple estimates a 150 bps annual return improvement.

Reduced planning time by up to 90%
Tasks that previously required hours of manual work now take minutes, with real-time scenario modeling.

Enhanced planning discipline and risk oversight
The firm uses Navigator alongside Addepar to monitor forward-looking beta, impairment risk and liquidity exposure.

Enabled multi-year strategy development
Stone Temple now builds 3–4 year pacing plans across vintages, asset classes and capital programs. “We can say: here’s your venture plan for the next four years. Here are the vintage years. Here’s how this affects return and liquidity,” says David Ward

Improved client engagement
Families gain visibility into how portfolios evolve, helping them stay committed to long-term investment strategies. David Ward adds, “We build conservative models. Over time, families see that what we’ve shown them is actually more cautious than what plays out and that builds trust.”

Capital call and distribution forecast for a private equity buyout model, shown with net cash position over a 15-year period

Navigator gives us a dynamic framework we can use in every client meeting — not just to show how things are playing out, but to give families a real feel for the decisions ahead.

David Ward, Founder & Coo

CONCLUSION

Stone Temple didn’t set out to use Navigator. They set out to build the best investment and advisory platform possible for their clients. Executing their vision requires more than expertise — it demands infrastructure. With Navigator, they found a platform that could bring structure to complexity, clarity to uncertainty and discipline to private market investing.

Today, Stone Temple builds deeply customized portfolios with confidence, knowing their planning is as dynamic and resilient as the investments they pursue. "These are very real problems everyone has to solve to invest successfully. Once we committed, Navigator became an extremely effective infrastructure for us," says Alex Herman.