BBB vs AAA Credit Spread
BBB OAS was approximately 100 basis points in April 2026; AAA OAS was approximately 40 basis points. The BBB-AAA spread of roughly 60 basis points is near 25-year tights, last seen briefly in 2017 to 2018 and pre-2008.
Also known as: BBB Credit Spread (BBB spread) · AAA Credit Spread (AAA spread)
Why This Comparison Matters
BBB OAS was approximately 100 basis points in April 2026; AAA OAS was approximately 40 basis points. The BBB-AAA spread of roughly 60 basis points is near 25-year tights, last seen briefly in 2017 to 2018 and pre-2008. The long-term average is approximately 100 basis points. The spread captures the price of quality differentiation within investment grade: when narrow, markets assume BBB and AAA defaults are similarly low; when wide, markets are pricing differential default risk between high-quality and lowest-quality IG. The pair is one of the cleanest IG-side recession warnings, with widening typically preceding both broader credit stress and equity correction.
What BBB and AAA OAS Capture
Investment-grade corporate bonds are rated AAA through BBB- by S&P (equivalent to Aaa through Baa3 by Moody's). The IG universe is roughly $9 trillion in outstanding US corporate debt. AAA-rated bonds are the highest quality, typically issued by the most financially conservative companies (Microsoft, Johnson & Johnson, Apple). The current AAA universe is small (only about 2 percent of IG market, totaling perhaps $200 billion) because corporations have generally moved toward higher leverage and ratings have drifted lower over decades.
BBB-rated bonds are the lowest tier of IG, with bonds rated BBB+/Baa1 through BBB-/Baa3 sitting just above the IG-HY boundary. BBB makes up roughly 50 percent of the entire IG market in 2026, totaling approximately $4 trillion outstanding. The growth from 30 percent of IG in the early 2000s reflects corporate balance sheet evolution toward higher leverage. The BBB and AAA OAS series are released daily by ICE BofA via FRED (BAMLC0A4CBBB and BAMLC0A1CAAA respectively).
The Credit Quality Curve
Within investment grade, ratings produce a hierarchy of credit spreads. April 2026 readings: AAA approximately 40 basis points, AA approximately 51 basis points, A approximately 75 basis points, BBB approximately 100 basis points. Each step down in rating adds 10 to 30 basis points of spread, reflecting incremental default risk. The pattern is non-linear: the BBB-A jump (25 basis points) is larger than the A-AA jump (24 basis points), which is larger than the AA-AAA jump (11 basis points).
The non-linearity reflects accelerating default risk near the IG-HY boundary. AAA defaults are essentially zero (no AAA US corporate has defaulted since 1990). AA defaults are very rare (less than 0.1 percent annual). A defaults are uncommon (less than 0.5 percent). BBB defaults are still rare but more material (1 to 3 percent in recession years). The BBB-AAA spread captures the cumulative quality premium: a spread of 60 basis points implies markets price BBB at 60 basis points more risk-compensated than AAA, even though both are technically investment grade.
Conditional Forward Response (Tail Events)
How AAA Credit Spread has historically behaved in the 5 sessions following a top-decile or bottom-decile daily move in BBB Credit Spread. Computed from 1,295 aligned daily observations ending .
Following these triggers, AAA Credit Spread rises 0.53% on average over the next 5 sessions, versus an unconditional baseline of +0.18%. 130 qualifying events; AAA Credit Spread closed positive in 45% of them.
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Frequently Asked Questions
What is the current BBB-AAA spread?+
Approximately 60 basis points in April 2026. BBB OAS at approximately 100 basis points, AAA OAS at approximately 40 basis points. The spread is near 25-year tights, last seen briefly in 2007 (pre-financial-crisis), 2017 to 2018, and the current 2024 to 2026 period. Long-term average is approximately 100 basis points. Crisis peaks: 2008 to 2009 reached 400+ basis points; March 2020 hit 320 basis points; October 2022 reached 125 basis points (mild stress). The current compression reflects strong demand for yield and limited differentiation between high-quality and lowest-quality IG.
Why does the BBB-AAA spread matter?+
It captures the price of quality differentiation within investment grade. When narrow (current configuration), markets assume BBB and AAA defaults are similarly low, indicating credit cycle complacency. When wide, markets are pricing differential default risk, often as a precursor to broader credit stress. The 2007 to 2008 episode is the textbook example: BBB-AAA spread widened from 60 basis points in mid-2007 to 150 basis points by March 2008 (before the formal recession start) and ultimately to 400+ basis points in November 2008. The widening provided 6 to 9 month forward warning of equity correction.
What is the credit quality curve?+
Within investment grade, ratings produce a spread hierarchy. April 2026: AAA ~40 basis points, AA ~51 basis points, A ~75 basis points, BBB ~100 basis points. Each step down adds 10 to 30 basis points of spread reflecting incremental default risk. Default rates: AAA essentially zero (no AAA US corporate default since 1990), AA less than 0.1 percent annual, A less than 0.5 percent, BBB 1 to 3 percent in recession years. The non-linearity (BBB-A jump larger than A-AA jump) reflects accelerating default risk near the IG-HY boundary. The 60 basis point BBB-AAA spread captures the cumulative quality premium across all four IG tiers.
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Data sourced from FRED, CoinGecko, CBOE, and other providers. This page is for informational purposes only and does not constitute financial advice. Past performance does not guarantee future results.