Exchange-traded funds have lost money but gained popularity among investors this year.

A recent survey from State Street Global Advisors, the asset management arm of State Street, shows that the nation s 897 exchange-traded funds held $772 billion in assets under management through June 30. Although that s a 0.4% drop for the year to date, it compares favorably with the benchmark S&P 500, which fell 7.6% during the same period, and indicates that some investors are still putting money into ETFs in a difficult market.

"What started out as a very bullish year for equities has really moderated," says Tom Anderson, head of ETF strategy and research at State Street, which markets the SPDR family of ETFS. "ETF assets, though, have increased in the course of the year, because investors have put money into fixed income and commodities. Those are two of the fastest-growing investment categories."

ETFs offer individual investors access to investments that would otherwise be tough to trade. The convenience and liquidity they offer have helped drive some of the recent gains among State Street s offerings. For example, the SPDR Gold Shares fund, up 10.2% for the year to date, pulled in $1.6 billion in new money in June, and has attracted $7.6 billion for the year to date.

Some ETFs have also benefited from a broad change in market sentiment. "We're seeing some shifts in terms of where people are putting their money," says Tom Graves, an analyst at Standard & Poor s.

Only types of ETFs that have grown their assets under management this year: bond funds, up 21.1% through June; commodity funds, up 16.7%; and dividend-producing funds, up 12.9%. Heavily leveraged or inverse funds, largely based on derivatives and generally seen as too volatile for small investors, are up 6.3%.

The big losers have been currency funds, down 29.5% and global equity funds, down 12.0%.

Even as investors keep putting money into ETFs, some say the growth of the industry means some funds will be left by the wayside. Ron Rowland, president of Austin, Texas-based Capital Cities Asset Management, maintains the "ETF Deathwatch" site, an online record of funds on the brink. He says competition is making some funds cheaper and some less likely to survive.

Rowland gives a newly launched ETF six months to accumulate assets and start to establish some trading volume. Allowing for that leeway, the end of last year now appears to have been a tough time to launch exchange-traded funds, he says.

Rowland said Wednesday on his blog that 10 of the 23 products launched in December 2009 are now on Deathwatch. As of July 14, there were 133 ETFs on shaky footing, up 54% from June and the highest total since last August, when the list had 142 entries. The jump is partly due to a market slowdown, and partly to market saturation, Rowland says. Although the number of new funds has been growing, the number of indexes on which many are ETFs based has not kept pace.

"The investing public just can't keep up with all the new products, and as a result some go totally unnoticed," he says. "Either they're not noticed or there's nothing that distinguishes them from existing products."

Some ETFs have tried to set themselves apart on price, and investors may be able to save some money with a bit of comparison shopping.

Vanguard's aggressive entry into the ETF business means investors who once paid 0.72% for the iShares MSCI Emerging Markets Index fund can now own ETF shares of Vanguard's Emerging Markets Stock Index fund for 0.27%. Both funds attempt to track the performance of the same index.

Rowland calls the 45-basis-point difference significant and says the price wars will eventually give bigger players in the ETF business an advantage. "Perhaps they're trying to establish a beachhead, get products out there and develop a track record," he says. "If they've targeted the right niche, they can let those products be a financial loser for them for a number of years because they think it's the correct move for the long term. Smaller companies don't have the deep pockets to do that."