Transaction-based benchmarks providing transparent measures of funding and credit-market conditions, developed in alignment with IOSCO Principles for Financial Benchmarks, are now administered by STOXX as complementary credit-spread benchmarks to the Secured Overnight Financing Rate (SOFR).
NEW YORK, United States & ZUG, Switzerland (September 15, 2026) – STOXX Ltd., part of the ISS STOXX group of companies, today announced the launch of the iSTOXX® USD Across-the-Curve Credit Spread Index (AXI) and the iSTOXX® USD Financial Conditions Credit Spread Index (FXI), in collaboration with SOFR Academy, Inc. The transparent, rules-based indices are designed to complement the Secured Overnight Financing Rate (SOFR).
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The indices, originally created in 2021 and launched in July 2022, have been continuously refined and enhanced since launch, informed by feedback from private-sector market participants and public-sector stakeholders, and are now calculated, governed and published by STOXX under its established benchmark-administration framework. The transition to STOXX represents a major milestone in the institutionalization and broader market implementation of USD AXI and USD FXI.
The development comes as financial markets continue to adapt to the post-LIBOR environment created by global benchmark reform following the 2008 financial crisis. During that period, regulators identified significant shortcomings in reference rates that relied heavily on judgement-based submissions rather than observable transactions, leading to more objective, transaction-based benchmarks such as SOFR.
While SOFR has become the foundation of the U.S. dollar interest-rate market, it was intentionally designed as a near risk-free rate and does not reflect changes in bank funding costs or broader credit conditions. The AXI and FXI methodologies were devised to help market participants observe and manage those credit-spread dynamics through transparent, transaction-based benchmarks and offer them a true reference of funding conditions. Their development also reflected market demand from financial institutions, alongside broader post-LIBOR policy discussions encouraging private-sector innovation in benchmark design. The indices’ continued evolution has been informed by engagement with financial institutions, leading academics and public-sector stakeholders focused on resilient SOFR-based markets.
USD AXI and USD FXI are designed to reflect prevailing conditions in wholesale funding markets. USD AXI measures the recent cost of wholesale unsecured debt funding for publicly listed U.S. bank holding companies and commercial banks. USD FXI applies the same methodology to a broader universe that also includes non-bank financial institutions and U.S. corporate debt.
The indices incorporate eligible transactions across maturities ranging from overnight to five years. Their longer-term bond components use transaction data reported through the Financial Industry Regulatory Authority’s Trade Reporting and Compliance Engine (FINRA TRACE), while their short-term components use transaction data from the Depository Trust & Clearing Corporation (DTCC). No transactions from private markets, or from unregulated proprietary exchanges or platforms, are used as inputs.
These design features distinguish USD AXI and USD FXI from earlier credit-sensitive benchmark proposals as potential substitutes for USD LIBOR. USD AXI and USD FXI are designed as transparent spreads to be used alongside SOFR—not as replacements for SOFR—thereby preserving SOFR as the core risk-free rate. Their across-the-curve methodology provides a broader and more resilient measure of credit conditions without detracting from liquidity in SOFR or the established SOFR-based derivatives market.
In a 2024 limited-assurance review, Promontory Financial Group (IBM Promontory) assessed relevant IOSCO Principles applicable to the design and operation of the USD AXI and USD FXI benchmark framework, including Principle 6, Benchmark Design; Principle 7, Data Sufficiency; and Principle 9, Transparency of Benchmark Determinations. Promontory Financial Group concluded that these principles were fully implemented.
STOXX Ltd. is recognized as a third-country benchmark administrator under Article 32 of the EU Benchmarks Regulation and is supervised by the European Securities and Markets Authority (ESMA), providing an established regulatory framework for the administration of the indices in Europe. Further information on the governance, oversight and compliance framework for USD AXI and USD FXI is available in STOXX’s June 30, 2026 Governance, Oversight and IOSCO Compliance Framework letter.
The addition of USD AXI and USD FXI broadens STOXX’s benchmark offering in credit-spread and fixed-income markets, with potential applications in commercial lending, derivatives, asset-liability management, and financial risk management. The index methodologies are also designed to remain representative over time, adapting to changes in funding markets, and across different market environments, including periods of financial stress[1].
“We are pleased to assume administration and publication of USD AXI and FXI and to support their continued development as transparent, rules-based benchmark solutions,” said Axel Lomholt, General Manager, STOXX. “Robust governance, transparency and reliability are fundamental to confidence in financial benchmarks. STOXX’s established benchmark-administration framework, regulatory standing, and global calculation and distribution capabilities provide the strongest possible institutional foundation for these indices.”
“The launch of USD AXI and FXI by STOXX is an important milestone for these benchmark credit spreads and for the continued evolution of the post-LIBOR financial system,” said Marcus A. Burnett, Chief Executive Officer, SOFR Academy. “At a time of heightened economic, technological and geopolitical uncertainty, resilient financial infrastructure that supports the continued flow of credit is increasingly important.”
For further commentary from SOFR Academy and other market participants, please see the corresponding SOFR Academy announcement here.
[1] In the 2025 Journal of Finance article “Bank Funding Risk, Reference Rates, and Credit Supply,” Harry Cooperman, Darrell Duffie, Stephan Luck, Zachry Wang and Yilin Yang find that a transition to risk-free reference rates can increase bank funding risk, potentially dampening credit supply, while adding a benchmark credit-spread component can help mitigate those effects.
About STOXX
STOXX® and DAX® indices comprise a global and comprehensive family of more than 20,000 strictly rules-based and transparent indices. Best known for the leading European equity indices EURO STOXX 50®, STOXX® Europe 600 and DAX®, the portfolio of index solutions consists of total market, benchmark, blue-chip, sustainability, thematic and factor-based indices covering a complete set of world, regional and country markets. STOXX and DAX indices are licensed to more than 550 companies around the world for benchmarking purposes and as underlyings for ETFs, futures and options, structured products, and passively managed investment funds. STOXX Ltd., part of the ISS STOXX group of companies, is the administrator of the STOXX and DAX indices under the European Benchmark Regulation. stoxx.com
About SOFR Academy
SOFR Academy, Inc. is an American financial market infrastructure company focused on developing benchmark credit-spread solutions designed to complement risk-free reference rates and support resilient lending and funding markets globally. The firm developed the Across-the-Curve Credit Spread Index (AXI®) and the Financial Conditions Credit Spread Index (FXI®), transaction-based benchmark credit spreads intended to enhance credit transmission, lending continuity and financial stability in the post-LIBOR financial system. sofr.org
About ISS STOXX
ISS STOXX provides actionable insights through its comprehensive product offerings, proven expertise, and high-quality data that capital market participants around the world can use to inform their decision-making. Across indices, investment stewardship, corporate governance, sustainability, and fund intelligence, institutional investors and companies rely on us to help them manage investments, strengthen their governance practices, and bring new products to market. ISS STOXX, which is owned by Deutsche Börse Group, employs approximately 4,000 professionals operating across 34 locations in 20 countries. ISS STOXX’s clients include many of the world’s leading institutional investors and corporate issuers who turn to ISS STOXX for its objective and varied offerings.
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