Lloyd’s of London more than doubled investment income in the first half of the year as the world’s oldest insurance market benefited from its holdings in U.S. corporate debt.

Lloyd’s reported investment income of 642 million pounds ($1.05 billion) and a return of 1.3 percent in the six months to June 30, according to a statement. That’s up from 247 million pounds from a year earlier. Pretax profit climbed 21 percent to 1.67 billion pounds amid lower-than-average catastrophe claims.

“Investment income is up but it’s historically back to levels 2010-2012,” John Parry, finance director at LLoyd’s, said in a telephone interview. “Gains in corporate bond holdings, particularly in the U.S., and another flattening of the yield curve and bit of credit spread tightening has helped.”

Parry said Lloyd’s asset allocation remained conservative with 24 percent of holdings invested in government bonds and 40 percent in corporate credit. He cited a “tiny trend” to buy less credit due to rating agencies assigning less AAA ratings rather than a rotation into riskier assets.

Gross written premiums fell 4 percent to 14.86 billion pounds in the first half as pricing fell about 3 percent, Parry said today.