Markets rallied for a second day after the Federal Reserve stepped in to boost the U.S. economy with a plan to buy $40 billion in mortgage debt monthly.

The open-ended support, which will help keep interest rates lower, helped push the S&P Retail Index up 0.6 percent, or 3.95 points, to 669.26 — the index’s best close on record. The Dow Jones Industrial Average gained 0.4 percent, or 53.51 points, to 13,593.37, after rising more than 200 points Thursday.

Although the Fed move boosted the stock market, it was also a worrying sign that chairman Ben S. Bernanke sees the recovery as weak enough to require what amounts to a third shot in the arm. The day’s gainers included Fossil Inc., up 11.4 percent to $93.60; The Buckle Inc., 4.4 percent to $47.60; Sears Holdings Corp., 3.2 percent to $61.71; Tumi Holdings Inc., 3.1 percent to $26.11, and Warnaco Group Inc., 2.7 percent to $55.20.

In Europe, investors weighed in for the first time on the Fed’s boost to the U.S. economy and approved. Madrid’s IBEX 35 shot up 2.8 percent to 8,154.50, as Milan’s FTSE MIB rose 2.3 percent to 16,624.45, Paris’ CAC 40 rose 2.3 percent to 3,581.58, London’s FTSE 100 increased 1.6 percent to 5,915.55, and Frankfurt’s DAX advanced 1.4 percent to 7,412.13.

The strongest stocks included Burberry Group, up 3 percent to 10.82 pounds after earlier this week losing close to 25 percent of their value on warnings of a softening in demand; LVMH Moët Hennessy Louis Vuitton, 2.8 percent to 126.80 euros; Hermès International, 2.4 percent to 219.40 euros, and Tod’s, 1.6 percent to 88.05 euros.

The euro traded for $1.29 compared with the dollar and the pound went for $1.61.