Skip to Main Content
The Credit Market Lens

What Would The Merton Model Say About AI Capital Spending?

AI-driven capex is widening the gap between opportunity in equities and risk in credit.
 What Would The Merton Model Say About AI Capital Spending?
What Would The Merton Model Say About AI Capital Spending?
Headshot of Lotfi Karoui
 | {read_time} min read

Figure 1: Sentiment toward the tech sector has notably improved in the equity market so far this quarter …

Source: Bloomberg, PIMCO as of 14 May 2026. Line shows the arithmetic average of the total return of equities in U.S. hyperscalers, minus the total return of the S&P 500 Index.
The credit market has shown more restraint. Hyperscalers have underperformed the broader investment grade market in recent weeks (see Figure 2) as investors digest the implications of a multi-year, debt-funded capex cycle. Software, meanwhile, has yet to catch a bid in the leveraged loan market, where AI disruption risk remains priced in (more on this below).

Figure 2: … but credit investors have shown more restraint

Source: Bloomberg, PIMCO as of 14 May 2026. Methodology: Compute the average option-adjusted spread (OAS) of longest-dated bonds issued by hyperscalers and divide by the average OAS of long-dated bonds in the Bloomberg US Investment Grade Corporate Index ex hyperscalers.

The Merton framework helps explain the bifurcation between equity and credit price moves. A leveraged bet on AI infrastructure with uncertain and potentially volatile payoffs tends to raise the value of the equity call even as it makes the bondholders’ implicit put more risky. In Merton terms, asset values may be increased, but so is the strike price of the put.

For shareholders, the upside justifies the gamble. For bondholders, the downside is real and the upside belongs to someone else. That wedge – the classic asset substitution problem – is what credit investors are increasingly pricing, and until the re-leveraging impulse shows signs of reaching a plateau, the divergence across the capital structure is likely here to stay.

Figure 3: Software issuers have weighed on the leveraged loan index

Source: Bloomberg, PitchBook, PIMCO as of 14 May 2026. Data are from the Morningstar LSTA US Software Loan TR USD Index, the Morningstar LSTA US Leveraged Loan TR USD Index, and the S&P North American Expanded Technology Software Index.

Within the software sector, there has also been clear bifurcation between sponsored and non-sponsored issuers. Although private equity (PE) ownership/sponsorship had been viewed favorably during past periods of weakness, such as the COVID-19 pandemic, this is no longer the case. Loans issued by PE portfolio companies have been materially underperforming those issued by non-sponsored firms. Of course, at the index level one could cite differences in quality and sector composition as the driver of this performance differential, rather than just PE sponsorship. Therefore, to address this critique, we go deeper to show the result in two more robust ways.

First, we conduct a like-for-like comparison by focusing on B rated software loans in the S&P UBS Leveraged Loan Index, constructing one portfolio of sponsored issuers and another of non-sponsored ones. These portfolios control for differences in both credit quality and sector. Figure 4 shows that even within this tightly controlled subset, PE ownership has been a drag on performance.

Figure 4: The underperformance of sponsored issuers holds true even when looking at B rated software loans

Source: PitchBook, PIMCO as of 14 May 2026. Data are from the S&P UBS Leveraged Loan Index.
In the second approach, we use a regression-based framework. This method effectively compares two hypothetical portfolios of sponsored and non-sponsored loans in the same index that are otherwise identical in terms of industry and rating composition (see Figure 5). Here again, the result holds, suggesting that the underperformance is not simply a function of compositional differences, but rather reflects a more fundamental shift.

Figure 5: A regression-based approach shows significant spread compression between PE-sponsored and non-sponsored loans over the past two years

Source: PitchBook, PIMCO as of 14 May 2026. Data are from the S&P UBS Leveraged Loan Index. The line shows how much tighter or wider sponsor-backed loans have traded relative to comparable non-sponsored loans over time, measured in OAS basis points after controlling for rating and sector. Gray band represents a 95% confidence interval around that estimate.
The broader implication is that the market appears to have materially reassessed the extent to which PE sponsors can, or will, provide liquidity and funding backstops to their portfolio companies.

Figure 6: So far this year, AAA CLOs have outperformed their spread beta to leveraged loans

Source: Bloomberg, PitchBook, PIMCO as of 14 May 2026. Data are from the Palmer Square AAA CLO Index and Morningstar LSTA US Leveraged Loan TR USD Index.

Aside from the index-level containment, another main reason for the AAA CLO outperformance is structural subordination – that is, the order in which claims are contractually repaid, with senior tranches coming before junior ones. Even where software exposure exists within CLO portfolios, the deep subordination cushion at the AAA level means the bar for losses to reach the senior tranche is exceptionally high. AAA attachment points are deeply out of the money, and CLO portfolios tend to be diversified across hundreds of issuers and dozens of sectors.

Therefore, for AAA CLO spreads to reprice meaningfully wider, the stress would need to extend well beyond a single sector – it would require a systemic credit event producing default losses far above historical norms. That scenario remains firmly outside the baseline, particularly given the continued resilience of U.S. economic growth.

Michael Puempel and Gabriel Cazaubieilh contributed to this report.

See Credit Markets more Clearly

Subscribe to our LinkedIn Newsletter for data-driven perspectives on public credit liquidity, market structure, and the insights shaping what matters next. New analysis delivered regularly.
Expert Lotfi Karoui

Get Notified When New Articles Publish

Sign up today, and never miss an issue of The Credit Market Lens.

Thank you

Thank you for signing up. You will receive an email notification when the next issue of The Credit Market Lens publishes. 

Select Your Location


Americas

Asia Pacific

  • Japan

Europe, Middle East & Africa

  • Europe
Back to top

Leaving PIMCO.com

You are now leaving the PIMCO website.