The Oracle of Tampa and the Modern Portfolio Theory

At first glance, the recent Bloomberg article on the $3.2 billion City of Tampa Fire and Police Pension Fund reads like a referendum on Modern Portfolio Theory (MPT). To paraphrase the protagonist, Harold “Jay” Bowen III – the fund’s sole portfolio manager – his strategy is simple: observe the markets daily, make stellar stock picks, and outperform all the “eggheads” armed with sophisticated risk management tools.

That, essentially, is what Bowen and his nine-person firm, Bowen, Hanes & Co., have done for decades – running a straightforward portfolio of mostly stocks and bonds, while consistently outperforming peers in the Wilshire Trust Universe. For context, the pension fund posted a 32.2% return in its fiscal year ending September 2024.

Like many profiles before it, the article recounts the firm’s 50-year history of spectacular stock picks – Coke, Apple, and, more recently, Nvidia in 2019 – mirroring Buffett-esque performance. Bowen even openly mocks MPT’s core tenet that volatility equals risk.

And yet, ironically, Bowen’s track record is one of the strongest affirmations of MPT – the same theory for which Markowitz, Merton, and Sharpe won the Nobel Prize in 1990.

The world, one might say, divides into two camps: those who can watch magic tricks endlessly with awe, and those who leave a magic show sleepless, desperate to uncover the trick. MPT was invented for the second group – those who prefer to demystify returns and sleep soundly without needing melatonin. Some managers use factor models and risk analytics; others, like Bowen, rely on their intuition. Some pensions deploy BlackRock’s expensive Aladdin system to dissect portfolio risks; others entrust everything to one manager’s instincts. Either way, everyone wants to sleep well at night.

But whether investors acknowledge it or not, MPT operates under the hood. To demonstrate this, we used Professor William Sharpe’s returns-based style analysis (RBSA) via the MPI Stylus Pro system.

RBSA is one of the strongest validations of Modern Portfolio Theory: in a diversified portfolio, individual stock bets either offset each other or coalesce into broader themes, enabling the portfolio’s performance to be replicated or explained using a long-only mix of generic market indices or factors – without any knowledge of the actual holdings. The key lies in selecting indices that plausibly reflect the manager’s investable universe. While the short return history (annual returns for pensions) presents a challenge to traditional regression methods, modern dynamic models can still extract meaningful and robust estimates.