Fund giant Vanguard is making the biggest cuts to expense ratios in its history. On average, the asset manager is slashing fees by 20% across 168 share classes of 87 funds. Collectively, the fee reductions should save Vanguard investors more than $350 million this year alone.

Vanguard’s new fee cuts are a win for retail investors — helping to boost long-term returns. Here's what a low expense ratio means.

Asset manager Vanguard said on Monday it was lowering the cost of investing across its fund lineup in its largest cut ever and estimated that this would translate into savings of more than $350 million for its investors this year.