U.S. real estate investment trusts fell the most in 19 months as the Federal Reserve said it could scale back bond purchases this year, fueling concern that rising interest rates will increase acquisition and refinancing costs.

The Bloomberg REIT Index declined 3 percent, the most since November 2011. The gauge has lost 12 percent from an almost six-year high on May 21 amid speculation the Fed would reduce bond purchases, which have kept borrowing costs near record lows.

Fed Chairman Ben S. Bernanke said Wednesday that policy makers may end the purchases in mid-2014 if the economy continues to improve, sending the yield on 10-year Treasury notes to a 15-month high. REITs are dependent on the capital markets to finance acquisitions and development because they can’t keep large amounts of cash on hand. They also are required to pay out most of their taxable earnings to shareholders, making them comparable to a bond investment.

“The cost of capital, both debt and equity, is really important,” Jim Sullivan, a managing director at Green Street Advisors Inc., a Newport Beach, California-based research company focused on REITs, said in a telephone interview. “That’s a strong headwind for any industry that’s capital intensive, including commercial real estate.”

Select Income REIT, a Newton, Massachusetts-based owner of single-tenant properties, fell the most today of the 129 members in the REIT index, losing 4.8 percent to $28.47. Indianapolis-based Simon Property Group Inc., the largest U.S. REIT, dropped 2.9 percent to $162.52.

The Bloomberg Healthcare REIT Index fell 4 percent today and has lost 18 percent from its May 21 high. The Bloomberg Single-Tenant REIT Index is down 17 percent from its recent peak, the second-worst performance among industry groups.

Single-tenant landlords, which own buildings rented to companies such as fast-food chains or pharmacies, typically have tenants with long leases. That gives the properties “bond- like” qualities that makes them less attractive to investors when rates rise, said Ryan Severino, senior economist at Reis Inc., a real estate data company in New York.