The US government shutdown combined with growing concern over the country's debt ceiling have led to renewed fears US equity markets could sell off heavily if the impasse continues.
PIMCO, the world's largest bond house, lost its position as the best-selling fund group in Europe in the first half of the year.
The managers of PIMCO's $28bn income range have upped exposure to the US mortgage sector after May and June's sell-off.
PIMCO's Bill Gross has likened the recent sell-off in bonds to the "Battle of the Somme", but said the group is well positioned to fight on in future.
Bill Gross' $268bn PIMCO Total Return bond fund saw record outflows of almost $10bn in June as investors' flight from fixed income continued in earnest, according to reports.
Leading strategic bond fund managers have cut their aggressive shorts on US treasuries, on the expectation the Federal Reserve may postpone plans to scale down QE if growth and inflation continue to undershoot.
GLG is to launch a global total return fund targeting LIBOR + 5% after expanding its macro investment team.
Bill Gross, the manager of the world's largest bond fund, has told investors selling treasuries they could be left disappointed if they overestimate the speed with which the Fed will wrap up QE.