As the global ETF industry approaches the $2 trillion mark, the fight for market share has gotten more intense.

In the U.S., providers are offering heavy discounts on fees to attract nervous investors, including industry heavyweights BlackRock and Vanguard.

Read: BlackRock announces ETF fee cuts

However, according to an FT report, industry experts assert providers must also consider other issues such as liquidity, spreads, tracking error and total return.

Read: BMO drops ETF fees

Signs of a fee battle have started to emerge in other parts of the world. Europe got its first taste a few years back when Deutsche Bank dropped its management fee for some ETFs to zero.

Read: ETFs let advisors do their jobs