WASHINGTON — Chairman Ben Bernanke ended weeks of speculation Wednesday by saying the Federal Reserve probably will slow its bond-buying program later this year and end it next year if the economy continues to improve.
The Fed’s bond purchases have helped keep long-term interest rates at record lows. A pullback in the Fed’s purchases probably would lead to higher rates on mortgages and other consumer and business loans.
Bernanke said the reductions would occur in ‘‘measured steps’’ and that the purchases could end by the middle of next year. By then, he said he thought unemployment would be around 7 percent.
The chairman likened any reduction in the Fed’s $85 billion-a month in bond purchases to a driver letting up on a gas pedal rather than applying the brakes. He stressed that even after the Fed ends its bond purchases, it will continue to maintain its vast investment portfolio, which will help keep long-term rates down.
The ultra-low borrowing rates the Fed has engineered have been credited with helping fuel a housing comeback, support economic growth, drive stocks to record highs, and restore the wealth America lost to the recession.
Anticipating higher rates, investors reacted Wednesday by selling both stocks and bonds. The Dow Jones industrial average closed down 206 points. The yield on the 10-year Treasury note shot up to 2.33 percent from 2.21 percent.
‘‘There’s fear you’ll see an expanding economy, which has a tendency to push up interest rates,’’ said Jack Ablin, chief investment officer of BMO Private Bank.
Some investors fear that higher rates will cause investors to shift money from stocks into higher-yielding bonds. Others fear that the economy might not be ready to absorb higher rates and consumers and businesses might curb borrowing.
The Fed issued an updated economic forecast, which sketched a brighter outlook. It said the ‘‘downside risks to the outlook’’ had diminished since fall.
The more upbeat forecast helps explain why the Fed thinks record-low rates may soon no longer be necessary. Low rates help fuel economic growth. But they also raise the risk of high inflation and dangerous bubbles in assets like stocks or real estate.
Speaking of the economy, Bernanke said, ‘‘The fundamentals look a little better to us.’’
He spoke at a news conference after the Fed ended a two-day policy meeting. After the meeting, the Fed voted to continue the pace of its bond-buying program for now.
Timothy Duy, a University of Oregon economist who tracks the Fed, called the statement ‘‘an open door for scaling back asset purchases as early as September.’’
The fact that the Fed foresees less downside risk to the job market ‘‘gives them a reason to pull back’’ on its bond purchases, Duy said.
Asked at his news conference whether it will be difficult for the Fed to clearly communicate its plans for scaling back the bond purchases, Bernanke agreed. ‘‘We are in a more complex type of situation,’’ he said.
In its statement Wednesday, the Fed said it would maintain its plan to keep short-term rates at record lows at least until unemployment hits 6.5 percent.
The Fed also released its latest economic projections Wednesday. Fed officials predicted that unemployment will fall a little faster this year, to 7.2 percent or 7.3 percent at the end of 2013 from 7.6 percent now. They think the rate will be between 6.5 percent and 6.8 percent by the end of 2014, better than its previous projection of 6.7 percent to 7 percent.
The Fed also said inflation was running below its 2 percent long-run goal, but noted that temporary factors were partly the reason. It said inflation could run as low as 0.8 percent this year. But it predicts it will pick up next year to between 1.4 percent and 2 percent.
Financial markets had been gyrating in the four weeks since Bernanke told Congress that the Fed might scale back its effort to keep long-term rates at record lows within ‘‘the next few meetings” — earlier than many had assumed.