The iShares U.S. Preferred Stock ETF (NYSEArca: PFF) was down more than 1% on Monday with volume doubling the daily average in the first 90 minutes of U.S. trading.

PFF was down sharply for the second straight day with ETFs hitched to many high-yielding sectors hitting a rough patch recently as interest rates move higher.

The preferred share ETF slipped below its 200-day moving average at Monday’s open before recovering somewhat. PFF hasn’t traded below this technical indicator since January 2012.

Preferred stock ETFs have been popular with investors seeking to boost yield in a low-rate environment. The funds are also known for their concentration in the financial sector.

Preferred shares are hybrid securities that combine features of stocks and bonds. They pay attractive dividends and are higher on the capital structure than common stocks, but preferred shareholders have no voting rights.

PFF pays a 30-day SEC yield of 5.51%, according to manager BlackRock.

Some analysts have been warning that that investors chasing yield in preferred stock ETFs could get burned if rates rise. [Are 6% Yields in Preferred Stock ETFs Worth the Risks?]

PFF experienced trading volume of more than 3.5 million shares on Monday morning, compared with average daily volume of 1.7 million the past three months.

During the financial crisis, the preferred stock ETF lost more than 70% of its value from the 2007 peak to the 2009 bottom.

iShares U.S. Preferred Stock ETF