ICE BofA 15+ Year US Corporate Index Option-Adjusted Spread

Starting in April 2026, this series will only include 3 years of observations. For more data, go to the source. The ICE BofA Option-Adjusted Spreads (OASs) are the calculated spreads between a computed OAS index of all bonds in a given rating category and a spot Treasury curve. An OAS index is constructed using each constituent bond's OAS, weighted by market capitalization. The US Corporate 15+ Year OAS is a subset of the ICE BofA US Corporate Master OAS, BAMLC0A0CM. This subset includes all securities with a remaining term to maturity of greater than or equal to 15 years. When the last calendar day of the month takes place on the weekend, weekend observations will occur as a result of month ending accrued interest adjustments. Certain indices and index data included in FRED are the property of ICE Data Indices, LLC (“ICE DATA”) and used under license. ICE® IS A REGISTERED TRADEMARK OF ICE DATA OR ITS AFFILIATES AND BOFA® IS A REGISTERED TRADEMARK OF BANK OF AMERICA CORPORATION LICEN