Exchange-traded fund pricing apparently is a race to the bottom.

In 2012 alone, the three biggest players in the ETF world — Blackrock (NYSE:BLK), State Street (NYSE:STT) and Vanguard — have cut the expense ratios on 17% of all existing ETFs, according to a Fox Business report. The three companies are responsible for 31% of exchange-traded funds.

The expense ratio is what the firm charges for various expenses — such as fund manager’s pay, informational materials and other administrative costs — and is baked into the fund’s returns.

The price slashings come as these companies and others try to stand out amid a large and growing crowd of ETFs. As State Street reported earlier this month, exchange-traded fund assets in the U.S. alone have grown to an all-time high $1.18 trillion across more than 1,200 funds — 74 of them added this year alone.

Vanguard, also known for its low-expense mutual funds, averages a mere 0.16% expense ratio across its ETFs. It dropped the Vanguard MSCI Emerging Markets (NYSE:VWO) ETF to 0.2% from 0.22%, making it one of the cheapest ways to get into emerging-market stocks. And State Street Global Advisors — sponsor of the United States’ oldest ETF, the SPDR S&P 500 ETF (NYSE:SPY) — cut expense ratios on nine of its SPDR sector ETFs to one basis point lower than their Vanguard counterparts.

Meanwhile, BlackRock has spent this year issuing 35 new low-cost funds averaging 0.48% in expenses, according to the report.

However, the two cheapest ETFs are sponsored outside of the big three. FocusShares’ Focus Morningstar US Market Index ETF (NYSE:FMU) and Focus Morningstar Large Cap Index ETF (NYSE:FLG) can be had for a 0.05% song.

Check out InvestorPlace‘s ETF Investing section for fund analysis and news.

The full Fox Business report can be viewed here.

— Kyle Woodley, InvestorPlace.com