Calamos CEO John Koudounis Warns Investors of Blind Spots in Stock Picking

One of the greatest dangers in buy-and-hold stock picking is blind spots around an investor’s favorite holdings. It can be easy to miss the forest for the trees when major shifts are occurring.

In an interview, John Koudounis of Calamos Investments shared an apt warning as the specter of artificial intelligence continues to hover. Calamos is a global investment firm with about $48 billion in assets under management as of February 2026, including more than $20 billion in liquid alternatives.

Background on John Koudounis

Koudounis is the president and CEO of Calamos Investments, a Chicago-based diversified global investment firm. He joined Calamos in 2016 as part of a long-term succession plan set out by the firm’s founder, Chairman and Global CIO John P. Calamos Sr.

“My mandate was clear: take a firm with a deep heritage in convertibles and risk-managed strategies and scale it for today’s markets,” Koudounis said. “Under my leadership, we’ve nearly tripled assets under management to $48 billion and expanded our platform across alternatives, multi-asset, convertibles, fixed income, equity, and sustainable strategies. We’ve also been at the forefront of innovation in structured protection and digital assets—launching the world’s first protected Bitcoin ETFs, and we pioneered an entirely new category with our Autocallable Income ETFs — CAIE just won ‘Fund Innovation of the Year.’”

Before Calamos

Before joining Calamos, Koudounis spent many years in the global securities business, serving as president and CEO of Mizuho Securities USA, the U.S. broker-dealer arm of Mizuho Financial Group. While there, he led the firm’s transition into a full-service investment bank through the expansion of the debt and equity capital markets businesses. Koudounis helped broaden the firm’s client base and diversify its product set, transforming Mizuho into one of the leading global investment banks in the world.

Before Mizhuo, he served as managing director and head of fixed income for ABN AMRO Americas, helping drive the firm’s capital markets growth. Koudounis helped grow the division to the point where Royal Bank of Scotland acquired ABN AMRO in what was the largest bank merger in history.

“In addition to my executive roles, I stay very close to the markets,” Koudounis added. “I speak at conferences around the world and appear frequently on financial news networks to discuss macro trends, volatility, and how investors can use risk-managed strategies to build and preserve wealth.”