The Math Aint Mathing

Tax-aware long-short strategies and the risk budget you did not know you spent

By Monisha Jayakumar, Chief Investment Officer

Tax-aware portfolio construction is not a one-time problem. We believe that for most,  taxes should be a persistent, material consideration across nearly every allocation decision you make. The question is not whether to be tax-aware. The question is how much risk you are accepting in pursuit of that efficiency.

We think that a well-constructed tax-aware long-short strategy runs on two engines. The first is an investment engine; active security selection with a deliberate tilt toward securities expected to outperform, generating real alpha over time. The second is a tax engine that systematically harvests losses embedded in the normal course of portfolio trading, not as an afterthought but as a structural feature of how the portfolio is managed.

We find that if you ignore the investment engine, you lose the source of the losses. Ignore the tax engine, and you leave the harvesting opportunity on the table.

For the strategy to have economic substance, both engines need to be genuinely working. But engines need a frame to sit in. We believe that frame is the strategy’s risk contribution to the total portfolio: how much active risk it adds, where it adds it, and whether the portfolio can absorb it without compromising the allocations that are supposed to do different jobs. In our research, we find that the size of the strategy beyond what the risk budget can accommodate, with even two well-functioning engines, can produce a bad outcome.

When the two work together within a disciplined risk framework, We find the result is a strategy that earns its place in a sophisticated portfolio. The rest of this paper is about making sure the math does too.

Two very different strategies, one conversation

At the conservative end, a modest long-short extension typically runs 10%–30% short with net market exposure of approximately 100% – such is the quintessential 130-30 with a security selection model and a sub 2% tracking error target. The short position funds additional longs, a hedged extension, not a directional bet. When the security selection model has a bad year, market beta provides a partial cushion. This is an enhanced equity allocation. It belongs in the beta core.

At the leveraged end, strategies may run 200% long, 100% short, or 200% short in market-neutral versions, with gross exposure well above 300%. Net exposure may still approximate 100%, but the gross positions are large, financing costs are real, and the security selection model is doing significantly more work. We find the tax alpha is higher in such scenarios. So is everything else. Shorting complexity, short squeezes idiosyncratic outliers – these are not edge cases at those levels of leverage. They are an inherent part of the operating environment.

This is a portfolio architecture decision first

Let’s start with where we believe the capital gains problem originates: concentrated single stock positions, private equity allocations, and high-conviction alternative strategies. These can be the 20–30% of the total portfolio where meaningful appreciation accumulates and where the tax liability is created.

We believe that Aris’s tax-aware long-short strategy addresses that problem. Its most sensible allocation comes from the beta core: 70–80% of the portfolio that tracks the market, runs at a beta of approximately 1.0, and carries modest tracking error. It is an enhanced broad market equity allocation. With this allocation, capital losses may be realized as a byproduct of normal portfolio activity.

We find the gains live in the concentrated/alternatives book. The tax offset mechanism belongs in the core book.

When the tax-aware strategy is treated as another high-conviction allocation, levered up to 200+ long, 100 short, or 200 short in market-neutral versions, and runs at 6–8% tracking error, the architecture is inverted. Risk has been added to the part of the portfolio intended to absorb it. That inversion is where the ratio of tax benefit to incremental total portfolio risk stops making sense..

We believe in evaluating the architecture from the total portfolio level through time, not just at inception.

Penny-wise, pound-foolish

Higher tracking error generates more tax alpha in our findings. The relationship is not linear, but the direction is clear: more active risk means more positions, more turnover, and more opportunity to realize losses and defer gains. At the aggressive end of the tracking error spectrum, the cumulative loss generation tends to become substantially higher than a conservative implementation. Compounding over time, that is a meaningful difference. On a significant allocation, the annual tax benefit is real, and we find the argument for running it harder is genuinely difficult to dismiss.

But, based on our analysis, the 3-sigma arithmetic does not care about the cumulative chart. At 6% tracking error, a 3-sigma event produces an active underperformance of 18 cents for every dollar invested; that is 6% multiplied by 3 standard deviations, the cost of a tail event per dollar at risk. The move up the tracking error spectrum from 1.5%- 6% buys more tax alpha meaningfully – but costs 13.5 cents in additional tail risk for every dollar invested before financing costs,  fees, and before the security selection model has a bad year.

Tax alpha and investment alpha are independent variables. We find that a strategy with strong loss harvesting and a broken security selection model does not produce a good outcome. It produces a bad investment with a reduced tax bill.

In these scenarios, the ratio of tail risk to tax benefit is not fixed – it deteriorates as the portfolio seasons. Net capital losses are highest in the early years and compress toward a steady state as the portfolio matures. The tail risk cost does not compress in lockstep with the potential tax benefits. If evaluating this strategy at inception, using Year 1 loss projections, one looks at the most favorable ratio the strategy will ever produce. The question then becomes whether the steady state ratio – not the inception ratio – justifies the allocation.

The math is not wrong. It is just incomplete. The question is whether the incremental benefit justifies the incremental risk added to the part of the book that was supposed to be the core of the portfolio. That answer lives in the marginal benefit of the tax-aware strategy – and in whether the marginal risk it adds is a risk you actually want to take.

A client carrying a highly concentrated single stock position already has elevated effective tracking error – potentially 8% or more – simply by virtue of that concentration. In that context, a higher tracking error long-short strategy may reduce aggregate active risk in the taxable book rather than add to it, while generating the losses needed to fund diversification in a tax-efficient way. But this is a short-term solution to a specific problem, not a permanent allocation. A poorly planned exit can crystallize the very tax event you deployed the strategy to solve. How you get out matters as much as how you get in. 

Question the answers. Answer the Questions.

A tax alpha projection tells you one thing. Before sizing a tax-aware long-short allocation, ponder these questions:

Due diligence framework

Architecture: Is this strategy sitting in the right part of your portfolio, beta core or alternatives?

Alpha: Would this security selection methodology (aka, the security selection model) be justified without the tax wrapper? Does the track record, net of all costs, justify that answer?

Risk: How many years of tax alpha does one bad year erase – and can your risk budget absorb that drawdown without compromising the rest of the portfolio?

The strategy should add up in the context of the total portfolio. Examining it in isolation is not due diligence. It is a starting point.

Q.E.D.

Disclaimer

This article is published by Aris Investing, a registered investment advisor. It is intended for informational purposes only and does not constitute investment, tax, or legal advice. The views expressed reflect the author’s analysis as of the date of publication and are subject to change without notice.

The strategies and concepts discussed are general in nature and may not be suitable for all investors. Tax-aware investing involves complex considerations that vary based on individual circumstances, including but not limited to, an investor’s tax situation, investment horizon, risk tolerance, and overall portfolio composition. Past performance of any strategy referenced is not indicative of future results.

Nothing in this article should be construed as a solicitation or offer to buy or sell any security. Prospective investors should consult their own investment, tax, and legal advisors before making any investment decisions.

Aris Investing is registered with the Securities and Exchange Commission. Registration does not imply a certain level of skill or training.