Businesses have added 4.5 million workers under a new program that provides tax breaks for hiring unemployed workers, the Treasury Department said Monday.

It is unclear, however, how many of those workers would have been added without the tax break.

President Barack Obama signed a law in March that exempts businesses hiring people who have been unemployed for at least 60 days from paying the 6.2 percent Social Security payroll tax through December. Employers get an additional $1,000 credit if new workers stay on the job a full year.

Treasury released a report Monday estimating that from February to May, businesses added 4.5 million workers who qualify for the tax breaks. Those businesses are projected to save $8.5 billion in taxes.

Immigration to rich countries dropped during the global economic crisis, reversing five years of annual increases as the demand for labor fell, the Organization for Economic Cooperation and Development said Monday.

A report showed that 4.4 million people migrated to the OECD's 31 member countries — the world's most developed economies — in 2008. That is a drop of about 6 percent from the year before.

The fall reverses five years of annual increases of 11 percent, the OECD said in its International Migration Outlook 2010.

National data suggest that international migration fell again in 2009.

Unemployment among male immigrants has risen more than among native counterparts because many immigrants worked in industries badly hit by the crisis, such as construction, hotels and restaurants, the OECD said. Still, few are returning home, it said.

In some countries, employment of female immigrants has risen as women take jobs to make up for lost income of their unemployed spouses, it said.

Law firm merger activity picked up after a sluggish first quarter in part due to a renewed increase in transatlantic marriages between large domestic firms and those headquartered in England.

Among the 10 mergers reported last quarter by legal consultancy Hildebrandt Baker Robbins -- one more than during that time frame last year -- was the union of Washington stalwart Hogan & Hartson and London-based Lovells to form Hogan Lovells, which the report characterized as the second-largest since Hildebrandt began tracking quarterly merger activity.

A second cross-border marriage of equals, between Chicago-based Sonnenschein Nath & Rosenthal and London's Denton Wilde Sapte, was announced last quarter but is not included in that figure because the merger will not be completed until later in the year.

Industry analysts say that after a period of caution, U.S. firms are once again looking for markets in which to expand -- and the obvious one for some is London, where many firms specialize in the kind of corporate transaction work that has long been the bread and butter of New York.

The Oregon Supreme Court has ruled that Philip Morris does not have to pay $100 million in punitive damages to the family of a smoker who sued the tobacco giant over its low-tar cigarettes.

The case, however, is going to another jury to decide just how much the death of Michelle Schwarz from lung cancer in 1999 will cost Philip Morris — and legal experts say it could easily be another big award.

A Multnomah County jury in Portland originally awarded the Schwarz family $150 million in March 2002 before the trial judge reduced it to $100 million.

On Thursday, the Oregon Supreme Court vacated the $100 million award and sent the case back to the trial court to reconsider the punitive damages after ruling the judge failed to properly instruct the jury.

The court said the judge should have told the jury it could not punish Philip Morris directly for harm caused to others besides Schwarz.

But the court also supported the trial judge, who had rejected jury instructions the tobacco company had requested.