The ETF business is top-heavy in terms of the biggest funds and the largest providers’ market share.

Together, the three biggest ETF sponsors — BlackRock’s (NYSE: BLK) iShares, State Street (NYSE: STT) and Vanguard — control more than 80% of the industry’s assets.

The U.S. marketplace is comprised of 1,443 exchange traded products from 51 sponsors with $1.27 trillion in total assets, according to XTF.

The two largest ETFs, SPDR S&P 500 (NYSEArca: SPY) and SPDR Gold Shares (NYSEArca: GLD), together account for nearly $200 billion.

In ETFs, the rich seem to get richer because of the traditional first-mover advantage. Investors also tend to gravitate to the largest and most liquid funds. However, an ETF’s liquidity is influenced by other factors aside from trading volume. [ETF Liquidity More Than Just Trading Volume]

Index Universe recently rated the five largest ETFs trading and have come up with the following list, reported by Allan Roth for CBS MoneyWatch. [Stock ETFs Rally on Fiscal Cliff Deal Hopes, Bargain Hunting]

The largest ETF is the SPDR S&P 500, which is also the first ETF to trade. The fund has been trading since 1993 and has $98.83 billion in assets. The ETF is a pure large-cap play and tracks the S&P 500 Index. The second largest ETF is the SPDR Gold Shares with $73.93 billion in assets. This fund us ultra popular with investors because it is physically-backed and gives investors exposure to the precious metal without physical delivery. [Vanguard Emerging Market ETF Index Switch: What Investors Should Know]

Coming in third is the Vanguard MSCI Emerging Markets (NYSEArca: VWO) with $54.96 billion in assets. Next year the fund will track an FTSE Index versus the MSCI Index, omitting the South Korea allocation. This is one of the most affordable broad-based emerging market fund trading. Fourth is the iShares MSCI Emerging Market Index (NYSEArca: EEM) with $38.19 billion. The ETF tracks the same index as VWO, but charges 0.67%. The iShares MSCI EAFE Index (NYSEArca: EFA) comes in fifth at $35.6 billion, and tracks international developed markets. [A Look at Emerging Markets as Fiscal Cliff Looms]

There are other options for any of the five ETFs mentioned. These are just the largest funds by assets under management.

Tisha Guerrero contributed to this article.