Jonathon Costello is a Client Portfolio Manager for fixed income strategies at Janus Henderson Investors, a position he has held since 2025. Prior to joining the firm, he was a client service executive at Western Asset Management from 2021. Before that, he was a senior investment specialist at Walsh Bay Partners from 2017. Previously, he was a portfolio manager and senior investment research analyst at Australian Unity from 2013. Earlier, he worked at K2 Asset Management from 2009, most recently as a business development manager from 2011. Jonathon began his career as a research analyst at S&P Global Ratings in 2007.

Jonathon received a Bachelor of Social Science degree in psychology from RMIT University and a Master of Business in banking and finance from Monash University. He holds the Chartered Financial Analyst and Chartered Alternative Investment Analyst (CAIA) designations and has 18 years of financial industry experience.