* Policymaker pitches dual thresholds for U.S. unemployment
Wants bond buys at least until 7.25-pct jobless rate
* Wants near zero rates until unemployment falls to 6.5 pct
* Fed looking to clarify what would prompt tighter policy
By Tim McLaughlin
WELLESLEY, Mass., Nov 1 (Reuters) - The Federal Reserve should buy bonds at least until the U.S. jobless rate falls below 7.25 percent, a top Fed official said on Thursday, pitching a plan that includes the first specific target for ending the central bank's quantitative easing program.
Under the proposal unveiled by Boston Fed President Eric Rosengren, who is one of 19 Fed policymakers, the U.S. central bank's large-scale asset purchases would continue as long as inflation expectations remained subdued and they would not necessarily stop once the 7.25-percent jobless threshold was crossed.
The U.S. unemployment rate was 7.8 percent in September. The government will report the October unemployment rate and job-growth numbers on Friday.
Wading deeper into the debate over what parameters the central bank should use for maintaining its ultra-easy monetary policy, Rosengren said he would like the Fed to keep interest rates near zero until the jobless rate falls as low as 6.5 percent.
That makes him the fourth Fed policymaker to offer specific guidelines for when the central bank should finally reverse the super-accommodative rates policy it has adopted to help the United States recover from the Great Recession.
The weak U.S. labor market and stumbling economic growth prompted the Fed in September to launch a third round of quantitative easing, or QE3, under which it is buying $40 billion worth of bonds per month, with no set end date.
The Fed has said it will buy mortgage debt and possibly Treasuries until the labor market outlook improves ``substantially'' - a term Fed policymakers are now attempting to define.
Rosengren's take is the most specific yet.
``My own personal assessment is that, as long as inflation and inflation expectations are expected to remain well-behaved in the medium term, we should continue to forcefully pursue asset purchases at least until the national unemployment rate falls below 7.25 percent and then assess the situation,'' said Rosengren, who regains a vote on Fed policy next year.
The policymaker, who is firmly on the Fed's dovish wing, told a Babson College audience that he thinks of unemployment at about 7.25 percent as a ``threshold,'' not a ``trigger'' that would automatically change policy. At that point, the central bank should broadly assess growth, inflation, and other economic measures before deciding on any more bond purchases, he said.
Other Fed policymakers have used only general terms to describe what they consider the ``substantial'' improvement in labor that would halt the bond buying.
Earlier on Thursday, Atlanta Fed President Dennis Lockhart cautioned about relying on a single indicator, such as unemployment, to determine when to end QE3.
The Fed has now bought some $2.3 trillion in long-term securities in an unprecedented drive to spur growth and revive the economy after the worst recession in decades.
PLAN FOR LOW RATES
Rosengren drew an even more dovish line in the sand on the federal funds rate, which the Fed has kept near zero since late 2008.
At the September meeting in which it launched the open-ended bond-buying plan, the central bank said it expected to keep rates ultra low through at least mid-2015, and that it will keep policy easy for a ``considerable time after the economic recovery strengthens.''
U.S. gross domestic product growth rebounded in the third quarter to a 2 percent annual rate, from the second quarter's tepid 1.3 percent pace. But the economy needs to grow by more than a 2.5 percent pace over several quarters to make substantial headway cutting the jobless rate.
Inflation, meanwhile, has remained stable just below the Fed's 2 percent target.
``My own personal view is that if inflationary pressures remain muted, then labor market conditions would need to be more like 6.5 percent unemployment to warrant the federal funds rate being lifted off the zero bound,'' Rosengren said.
According to the minutes of the last two policy meetings, the Fed appears to be moving closer to setting formal markers, such as inflation and unemployment, that would cause it to reverse the aggressive efforts to boost the U.S. economy.
In recent months, the presidents of three other regional Fed banks have touted their own plans for raising interest rates, citing both unemployment and inflation thresholds.
The Minneapolis Fed's Narayana Kocherlakota said he would tolerate inflation as high as 2.25 percent until the jobless rate is 5.5 percent. John Williams of the San Francisco Fed says he is OK with 2.5 percent inflation and fingered unemployment ``somewhat below'' 7 percent.
The Chicago Fed's Charles Evans - the first to pitch such a plan - also targets 7 percent joblessness and would allow inflation to rise as much as 3 percent.
Rosengren did not specify an inflation threshold. But he said: ``I would suggest that attempting to hold actual inflation in lockstep with our 2 percent target over short timeframes is probably not realistic.''
October's jobs report is expected to show non-farm employers added 125,000 jobs last month - not enough to prevent the jobless rate from edging a bit higher. U.S. unemployment was as high as 10 percent in 2009.