Why Solar Returns Don't Follow the Stock Market - And Why That Matters
By Hardik BhatiaPublishedMost investors think they are diversified. They own stocks across sectors, some bonds, maybe a REIT or two, perhaps a commodities ETF. On paper, it looks like broad exposure. In practice, when markets crash, nearly everything drops together.
The 2022 rate-hiking cycle proved this painfully. Stocks fell. Bonds fell. REITs fell. Crypto fell. The traditional 60/40 portfolio had its worst year in decades. The assets that were supposed to zig when stocks zagged did not zig.
True portfolio diversification requires assets whose return drivers are structurally independent from financial markets - not just assets with different labels. Fractional solar ownership is one of the few income-producing asset classes that meets this test. Its returns are driven by sunlight, electricity contracts, and operational execution - not by earnings calls, interest rate decisions, or trading sentiment.
This blog explains why that distinction matters, what the institutional data says about infrastructure correlation, and why owning solar stocks is not the same as owning solar projects.
Why Do Most "Alternative" Investments Still Move with the Stock Market?
The promise of alternative investments is diversification - returns that behave differently from stocks and bonds. The reality is more complicated.
REITs are publicly traded on stock exchanges. Their prices react to the same forces that move equities: interest rate expectations, risk sentiment, trading volume, and index inclusion. During the 2022 selloff, the FTSE NAREIT All Equity REITs index fell alongside the broader market - not because rents disappeared, but because valuations compressed as interest rates rose. The physical buildings were fine. The stock prices were not.
Commodities are theoretically uncorrelated with equities, but in practice, they are often driven by the same macroeconomic forces — growth expectations, dollar strength, and geopolitical risk — that move stocks. Gold, the classic safe haven, has delivered genuine decorrelation at times, but its performance during equity drawdowns is inconsistent.
Hedge funds, which charge premium fees for uncorrelated returns, have increasingly correlated with the S&P 500 as strategies have crowded and markets have become more interconnected. Many long-short equity hedge funds had a correlation above 0.5 to the S&P 500 during recent market cycles.
Even private equity, often cited as an alternative, is fundamentally tied to the same corporate earnings cycle that drives public equities. The valuation methodology is different (quarterly marks rather than daily pricing), which smooths apparent volatility — but the underlying economic exposure is similar.
The pattern is clear: most "alternatives" are alternative in name only. When the macro environment shifts — when rates rise, when liquidity tightens, when growth expectations fall — they move in the same direction as stocks, even if they move at different speeds.
True diversification requires different return drivers. Not just different labels.
What Drives Solar Investment Returns - and Why Are They Different?
The returns from fractional solar project ownership are driven by four factors, none of which are connected to financial markets.
Sunlight. Solar energy generation is a function of solar irradiance - the amount of sunlight hitting the panels. This is determined by geography, season, weather patterns, and panel orientation. India receives 4-7 kWh per square meter per day across most of the country, among the highest globally. The amount of sunlight hitting Rajasthan does not change because the Federal Reserve raised rates or because a tech company missed earnings expectations.
The PPA tariff. The Power Purchase Agreement defines the price per unit of electricity the solar project sells. This tariff is contractually locked - typically for 10 to 25 years, often with a 1-3% annual escalation clause. The price does not fluctuate with commodity markets, bond yields, or equity valuations. It is a fixed (or predictably escalating) contractual rate, set at the time of signing.
Off-taker payment. Revenue depends on the electricity buyer paying for the power consumed under the PPA. This is a commercial obligation, not a market trade. The buyer's motivation is straightforward: the solar electricity is cheaper than their alternative grid supply. Their incentive to pay is rooted in their own operating cost savings, not in stock market conditions.
Operational execution. Plant uptime, panel cleaning, inverter maintenance, and grid connectivity determine how much electricity actually gets generated and sold. These are operational variables managed by O&M teams on the ground. A well-maintained plant in Gujarat operates the same way regardless of whether the S&P 500 is at an all-time high or in a bear market.
None of these drivers has a causal connection to what happens in financial markets. A market crash does not reduce solar irradiance. A credit downgrade does not change the PPA tariff. A recession does not turn off the sun.
This is what structural decorrelation means. The income stream from a solar project is generated by a physical process (photovoltaic conversion), governed by a legal contract (the PPA), and influenced by operational conditions (maintenance, weather). Financial market variables do not enter the equation.
What Does the Data Say About Infrastructure Correlation with Equities?
The institutional data supports what the structural argument predicts.
According to an analysis published by Advisor Perspectives in February 2026, drawing on CBRE data, private infrastructure returns have demonstrated an average correlation to global equities of just +0.1 and to global bonds of -0.1. For context, a correlation of +1.0 means assets move in perfect lockstep, 0.0 means no relationship, and -1.0 means they move in opposite directions. A correlation of +0.1 is as close to zero as any major asset class gets relative to equities.
This is not a niche observation. The largest institutional investors in the world are acting on it.
KKR's 2026 Infrastructure Outlook, published in April 2026, makes the case directly. The report argues that infrastructure is "no longer simply a portfolio diversifier" but should serve as "a strategic core allocation — a foundation that combines structural growth with resilience." KKR's analysis notes that expected returns across public asset classes appear meaningfully lower over the next five years than what investors realized over the past five, and that "incremental performance is less likely to come from passive exposure" and more likely to come from "structural growth exposure and careful asset selection."
McKinsey's 2026 Global Infrastructure Report reinforces the point. Global infrastructure fundraising reached a record $200 billion in 2025, surpassing the previous high of $180 billion in 2022. McKinsey reports that limited partners - the institutional investors who allocate capital to funds — name infrastructure as the asset class they most want to increase their allocations to, driven by both diversification benefits and performance expectations.
The capital flows reflect the conviction. Private infrastructure assets under management surged from approximately $500 billion in 2016 to $1.5 trillion in 2024, according to CBRE data cited by Advisor Perspectives. That tripling of capital into infrastructure assets over eight years represents one of the fastest-growing segments in private markets.
PitchBook's Q2 2025 Private Capital Indexes show that the rolling five-year correlation between private market assets and the S&P 500 has been dropping - meaning the diversification benefit is strengthening, not weakening, over time.
For accredited investors considering fractional solar, the institutional trend is clear: the largest and most sophisticated investors in the world are increasing their allocations to exactly this type of asset — contracted, infrastructure-backed, uncorrelated with public markets.
How Does This Play Out in Real Portfolio Scenarios?
The portfolio construction argument for uncorrelated assets is not theoretical. It is mathematical — rooted in Modern Portfolio Theory and validated by institutional practice.
Consider a simplified comparison. A traditional 60/40 portfolio-— 60% US equities (S&P 500), 40% US bonds (Bloomberg Aggregate) - experienced its worst annual return in decades in 2022. Both asset classes declined simultaneously as the Federal Reserve raised rates. The supposed diversification benefit of bonds failed precisely when it was needed most.
Now consider reallocating 10% of that portfolio to an asset with a +0.1 correlation to equities and a target yield of 10-14%. The rebalanced portfolio would be 55% equities, 35% bonds, and 10% fractional solar.
In a year when equities decline and bonds provide limited cushion, the solar allocation continues generating contracted income from PPA-backed electricity sales, unaffected by market conditions. The 10% allocation acts as a stabilizer - not because solar returns are guaranteed, but because the factors that would cause solar to underperform (equipment failure, PPA default, severe weather) are entirely different from the factors that cause stocks and bonds to underperform (rate hikes, recession, earnings misses).
This is the core portfolio construction insight: adding an asset with different risk factors reduces the probability that everything in your portfolio declines at the same time. Diversification is not about spreading money across many assets. It is about spreading money across genuinely different return drivers.
The trade-off is real: the solar allocation is illiquid. You cannot rebalance it quarterly like you rebalance an ETF. It sits in the portfolio for the PPA duration, generating income but not available for tactical reallocation. For investors who can accept that trade-off, the portfolio-level benefits are compelling.
Why Do Solar Stocks and Solar ETFs NOT Provide This Diversification?
This is one of the most important distinctions in renewable energy investing, and it is widely misunderstood.
The Invesco Solar ETF (TAN) is the most widely held solar equity fund. Its performance history tells a striking story:
2020: +234% (pandemic recovery, blue wave expectations)
2021: -25% (profit-taking, supply chain fears)
2022: -5% (rate hikes, margin compression)
2023: -27% (while the S&P 500 gained approximately 26%)
2024: -38% (while the S&P 500 gained approximately 25%)
2025: +48% (policy optimism, AI energy demand narrative)
In 2023, TAN fell 34% from its year-start level at one point while the S&P 500 gained 14% over the same period. Solar stocks did not just fail to diversify — they amplified losses. The volatility is extreme, the correlation with market sentiment is high, and the return profile looks nothing like the contracted cash flow of a solar project.
Why? Because solar stocks are equities. Their prices are driven by earnings expectations, analyst ratings, interest rate sensitivity, supply chain dynamics, trade policy, and investor sentiment. When you buy TAN, you are buying shares in solar equipment manufacturers, project developers, and component companies — not electricity output from solar plants.
The difference is structural. Owning stock in a solar company gives you exposure to that company's management decisions, competitive positioning, and market valuation. Owning membership units in a solar project gives you exposure to sunlight, a PPA contract, and an electricity off-taker.
One is a financial market instrument. The other is a physical infrastructure asset. They share a sector label, but their return drivers are fundamentally different. An investor who buys TAN for "solar diversification" has not reduced their equity market correlation. An investor who buys fractional solar ownership has.
What Are the Trade-Offs of Adding Uncorrelated Solar to a Portfolio?
Decorrelation is not free. The structural independence from financial markets comes with its own costs and constraints.
Illiquidity is the price of decorrelation. The reason fractional solar is uncorrelated with the stock market is precisely because it is not traded on the stock market. There is no daily pricing, no exchange, no ability to sell when sentiment shifts. Your capital is committed for the PPA duration. This is a feature from a correlation perspective — it is what prevents solar from catching the contagion of market selloffs — but it is a constraint from a portfolio management perspective.
You cannot rebalance. In a traditional portfolio, you can sell overweight positions and buy underweight positions to maintain your target allocation. With a 10% allocation to fractional solar, that 10% is fixed until the investment matures. If equities rally and your stock allocation drifts from 55% to 65%, you cannot trim solar to rebalance. Portfolio rebalancing works around the solar allocation, not through it.
Concentration risk is project-specific. Unlike an equity index fund that spreads risk across hundreds of companies, a fractional solar investment may be concentrated in a single project or a small number of projects. This means project-level events — equipment failure, off-taker default, regulatory changes — can have an outsized impact on that specific allocation. Investing across multiple solar projects mitigates this, but it requires more capital than a single investment.
Due diligence is more intensive. Evaluating a solar project requires understanding PPAs, SPV structures, O&M contracts, and Indian energy regulation - a different skill set from evaluating a stock or an ETF. The learning curve is real, though resources like our Solar Investment Glossary and Risks Guide are designed to help.
The honest summary: fractional solar offers something rare in investment markets — genuine structural decorrelation from equities. The cost is illiquidity, currency complexity, and concentration risk. For investors who have already built a liquid, diversified core portfolio and are looking to improve risk-adjusted returns with patient capital, that trade-off is worth making. For investors who need full liquidity or cannot tolerate the complexity, it is not.
Frequently Asked Questions
How much of my portfolio should I allocate to fractional solar? There is no universal answer, and this is not investment advice. Institutional infrastructure allocations typically range from 5% to 15% of total portfolio value, according to McKinsey and KKR research. For individual accredited investors, the allocation should reflect your liquidity needs, investment horizon, and tolerance for illiquidity and cross-border complexity. A common approach is to start with a small allocation (5-10%) using capital you can commit for the full PPA duration without affecting your liquidity position.
Does solar perform better or worse during recessions? Fractional solar performance is largely independent of recessions because the return drivers - sunlight, PPA contracts, and electricity demand — are not cyclical in the way corporate earnings are. Electricity demand is relatively inelastic, and PPA-backed revenue continues regardless of GDP growth. However, currency risk may increase during recessions if emerging market currencies weaken, and off-taker credit risk may rise if the electricity buyer faces financial stress. The asset does not "outperform during recessions" in the way gold sometimes does - it simply continues generating its contracted return largely independent of the macroeconomic environment.
Can I combine solar with REITs for a diversified income portfolio? Yes, and there is a strong case for doing so. REITs provide liquidity, real estate exposure, and dividend growth potential, while fractional solar provides higher current yield, infrastructure exposure, and genuine equity market decorrelation. The two asset classes have very low correlation with each other — REITs are moderately correlated with equities, while solar is structurally independent. A portfolio combining both creates a more resilient passive income stream than either alone. For a detailed comparison, see our guide: REIT vs Fractional Solar: Which Delivers Better Passive Income?
About Sustvest
SustVest LLC is a Delaware-registered fractional solar investment platform offering SEC Regulation D 506(c) compliant investment opportunities in Indian solar energy projects. Through its US entity structure, Sustvest enables accredited investors and NRIs to own membership interests (units) in operating solar projects backed by long-term Power Purchase Agreements. Each project is held in a separate Indian SPV, with SustVest LLC owning 100% of each SPV. Investors receive proportional monthly cash distributions in USD, with a minimum investment of $500 and target returns of 10–14% XIRR. Project details, SEC filings, and real-time generation data are available at sustvest.com.
This content is for informational purposes only and does not constitute an offer to sell or a solicitation of an offer to buy any securities. Investments in private offerings under SEC Regulation D are speculative, illiquid, and involve a high degree of risk, including the potential loss of the entire investment. Fractional solar investments are available only to verified accredited investors as defined under SEC Rule 501(a). Past performance is not indicative of future results. The correlation data cited in this blog refers to private infrastructure as an asset class and may not precisely reflect the correlation characteristics of any individual solar project investment. Portfolio allocation examples are hypothetical and for illustrative purposes only. Prospective investors should carefully review the Private Placement Memorandum (PPM) and consult with their own legal, tax, and financial advisors before making any investment decision. SustVest LLC does not provide investment, legal, or tax advice.
Sources:
Advisor Perspectives / CBRE — "Infrastructure returns have demonstrated an average correlation to global equities and global bonds of just +0.1 and -0.1, respectively" (February 24, 2026)
KKR — "2026 Infrastructure Outlook: Infrastructure Is No Longer Optional" — infrastructure as "strategic core allocation" (April 13, 2026)
McKinsey — "Global Infrastructure Report 2026" — record $200B fundraising in 2025; LPs name infrastructure as top asset class for increased allocation (March 23, 2026)
Advisor Perspectives / CBRE — Private infrastructure AUM: $500B (2016) to $1.5T (2024)
PitchBook Q2 2025 Private Capital Indexes — Rolling 5-year correlation between private markets and S&P 500 declining
ETF.com — "TAN has plummeted 34% this year compared with a 14% gain in the S&P 500" (December 2023)
YCharts / Morningstar — TAN annual returns: +234% (2020), -25% (2021), -5% (2022), -27% (2023), -38% (2024), +48% (2025), +5% YTD (2026)
FundsIndia — INR/USD depreciation: 3.4% (10Y), 4.3% (15Y) annualized
IRENA / MNRE — India solar irradiance: 4-7 kWh/m²/day
Within Intelligence — "Infrastructure Outlook 2026: Infrastructure shifts up a gear" — record fundraising, energy transition and data center demand (March 11, 2026)