Investors have upped their interest in actively managed bond ETFs, pouring record capital into them in January as some paid up in hopes of stronger returns.

Vanguard Group Inc.’s biggest salvo yet in its campaign to cut fees for the investing masses presents industry rivals with a painful choice. Follow suit and lose potentially hundreds of millions in revenue — or hold the line and risk losing badly needed market share.

Vanguard announced on Monday that it has reduced management fees for 87 exchange-traded funds and mutual funds. This move is the largest fee cut in the company’s nearly 50-year history. The firm estimates that this decision will save investors $350 million in 2025 alone.