The exchange traded fund low-fee war has been ongoing and providers are banking on hopeful investors seeking to maximize returns. However, there is much more to ETF investing than lower fees, and critics argue that the ongoing fee cuts can be costly over time.

“Fidelity Investments is trimming fees at its largest index mutual funds and making some of its lowest-cost options accessible to a larger number of fund shareholders, including those with as little as $2,500 to invest. Fidelity’s moves affect mutual funds holding about $100 billion in assets, out of about $1.6 billion that the Boston-based company manages overall,” Associated Press reports. [Fidelity Fires Back in Ongoing ETF Fee War]

Fidelity Investments is the first mutual fund company to slash expense ratios and lower the amount of minimum capital it takes to invest in one.  The Boston firm, with $1.7 trillion in assets under management, said it would lower the expense ratio by 0.01 to 0.08 percentage point on certain share classes of its Spartan series of index funds beginning Jan. 1, reports Kristen Grind for The WSJ. [ETF Fee War Spills Over to Index Funds]

The catch is that most investors don’t realize that if they are changing out ETF or mutual fund providers and chasing low fees, they are making trades. And these trades are costly and can add up quick. In fact, brokerage costs are one of the biggest expenses when it comes to actively trading, while expense ratios only make up one part of the equation.

Financial advisers and fund analysts say the cost of constantly changing index-fund and ETF providers might not be worth the difference in what you pay. [The Darker Side of the ETF Fee War]