Cash continues to pour into dividend exchange traded funds, so much so that ETFs holding dividend stocks are now bigger, as a group, than funds that hold U.S. Treasuries.

Combined assets under management for dividend ETFs have surged to $80 billion this year from $50 billion a year earlier, Brendan Conway reports for Barron’s, citing Ned Davis Research. At $80 billion, dividend ETFs have easily toppled the combined AUM total of $67 billion for Treasuries ETFs, according to Barron’s.

Year-to-date, the three largest U.S. dividend ETFs – the Vanguard Dividend Appreciation ETF (NYSEArca: VIG), the iShares Select Dividend ETF (NYSEArca: DVY) and the SPDR S&P Dividend ETF (NYSEArca: SDY) have hauled in about $5 billion combined, according to Index Universe data.

The trio rank among the 26 largest ETFs of any stripe with. With almost $45 billion in combined assets, it is not a stretch to say investors have embraced these ETFs. Throw in the Vanguard High Dividend Yield ETF (NYSEArca: VYM) at almost $6.8 billion, and it becomes clear that 65% of all assets allocated to U.S.-listed dividend ETFs are devoted to just four ETFs. [Investors Play Defense With Dividend ETFs]

No equity investment is risk free and dividend ETFs are no exception. Risks pertaining to the aforementioned payout funds include exposure to interest rate-sensitive sectors and stretched valuations.

Valuations on defensive sectors like consumer staples, telecom and utilities are stretched relative to historical norms, indicating investors are paying up for yield and past dividend consistency. Knowing that these ETFs are chock full of pricey stocks is important because defensive sectors are usually expensive compared to the broader market, but those groups are now pricey relative to their own histories. [These Dividend ETFs Look Pricey]