Earlier this year, the global exchange-traded products (ETPs) industry broke through the $4 trillion in assets under management mark. At the end of April, the U.S. was home to nearly $2.7 trillion of that record amount, solidifying its status as the world's largest market for exchange-traded funds (ETFs). (For more, see also: May ETF Flows: International, Tech Funds Lead.)

That does not mean the U.S. is the only market driving ETF industry growth. Europe, which is actually home to more ETPs than the U.S., is another fast-growing ETF market.

At the end of April, the European ETF/ETP market had a combined $658 billion in assets under management, up from the previous record of $640 billion at the end of the first quarter, according to London-based ETF research provider ETFGI.

Now closing in on $700 billion in assets under management, Europe's ETF market has ample room for growth. By comparison, the seven largest U.S.-listed ETFs have more assets than the entire European ETP market.

“Fund-tracker Morningstar Inc. predicts that by 2020, ETFs listed in Europe will have more than $1 trillion in assets under management. Currently, there is about $700 billion invested in European ETFs, according to Jose Garcia-Zarate, associate director of passive-strategies research at Morningstar,” reports the Wall Street Journal.

Europe's ETF/ETP market is sprawling. At the end of April, 60 issuers offered 2,257 products combining for nearly 7,130 listings on 27 exchanges in 21 countries, according to ETFGI. The large number of listings comes by way of issuers offering similar products in multiple countries. For example, issuers in Europe will list similar if not identical ETFs in Frankfurt, Milan and Paris.

The European ETF market has some players that U.S. investors are already familiar along with others that are not active in the U.S. market. BlackRock Inc.'s (BLK) iShares unit, the world's largest ETF sponsor, holds a dominant footprint in Europe as well as the U.S. However, Lyxor Asset Management and Amundi are among Europe's largest ETF sponsors as well, but neither is on the U.S. ETF scene.

Other U.S.-based companies that are active in the European ETF market include State Street Global Advisors -- sponsor of the roster of SPDR funds -- along with Vanguard and WisdomTree Investments Inc. (WETF).

One element holding the European ETF market back relative to the U.S. is sparse adoption of ETFs among retail investors. While institutional investors are the primary drivers of ETF growth and usage in the U.S., individual investors represent a significant portion of U.S. ETF assets. In Europe, professional investors dominate the ETF market with little participation from ordinary investors.

“Still, Europe is at least five years, and some would say a decade, behind the U.S. in the adoption of ETFs. What’s behind the lag? Mr. Garcia-Zarate says one major reason is that Europe hasn’t had the same demand from individual investors the U.S. has,” according to the Journal.

As is the case in the U.S., equity ETFs are the preferred choice in Europe followed by fixed income funds. (For more, see also: Don't Doubt the Data: Bond ETFs Will Keep Growing.)