Billionaire Ken Fisher's eponymous firm is making a bold contrarian bet on long-dated US bonds, positioning itself to profit from what appears to be a market-bottom opportunity.

The $4 billion trade focuses on the longest-dated US Treasuries, signaling Fisher's firm believes yields—which have climbed to their highest levels in nearly two decades—are now poised for a rally.

This contrarian stance goes against prevailing market trends, where many investors have been fleeing long-duration bonds due to persistent inflation concerns and aggressive Federal Reserve rate hikes. By doubling down on these securities, Fisher's firm is essentially calling a top in yields.

The move underscores how Ken Fisher, founder of Fisher Investments, continues to deploy substantial capital through his firm's proprietary trading arm, leveraging deep market insights to identify potentially lucrative opportunities in fixed income markets.