NEW YORK (MarketWatch) -- Treasurys closed with heavy losses Thursday, after the benchmark yield hurtled above 5% for the first time since August 2006, on the heels of a global sell-off of government bonds triggered by foreign interest-rate hikes.
Selling pressure was intensified by the hedging strategies of many mortgage-backed securities portfolio managers that force them to unload Treasurys. There also is a trend among foreign central banks to diversify away from long-term Treasury notes.
Thursday's Treasury rout came on the heels of heavy overnight sales of German and other government bonds. The sell-offs were linked to mounting evidence that interest rates in many countries will stand pat or head higher.
The first factor is global growth and inflation, he explained, as illustrated by both the recent rate hikes and strong data reports in many countries. Marta singled out unexpectedly brisk Australian labor-market data that sparked much of the overnight bond selling.
In addition, there's mounting evidence of a structural demand problem, as foreign central banks diversify their currency reserves away from longer-term Treasurys, Marta said.
The third heavy pressure on Treasury prices as cited by Marta is linked to the deterioration of the subprime lending market. As loans made to less creditworthy borrowers go sour, managers of portfolios of mortgage-backed securities are forced to sell off Treasurys to hedge their weakening loans, he said.
This, in turn, is a phenomenon that feeds on itself. "As yields go up, the mortgage-backed securities guys have to adjust their hedges," Marta said. "This means they have to keep ramping up their sales of Treasurys."