Offshoring of U.S. manufacturing operations is not only outpacing reshoring but gaining strength, according to a new report from management consulting firm A.T. Kearney.

In 2015, A.T. Kearney reports, its U.S. Reshoring Index fell to -115, down from -30 in 2014. This is the fourth consecutive year when reshoring failed to keep pace with offshoring and the largest year-to-year decrease in the last 10 years, the company reported.

Even if the effect of raw material price declines is discounted by holding manufacturing input values constant relative to 2014 while ignoring that same effect on the value of offshore manufactured goods, the consulting firm found, the reshoring index would drop to -26, “still supportive of the view that the widely predicted reshoring trend seems to be over before it started.”

The A.T. Kearney study clashes with a recent report from Boston Consulting Group, which found that nearly a third of large corporations with operations in the U.S. that were planning to add capacity for the U.S. market would increase production in the U.S. Only 20% said they would do so in China, reversing earlier findings. Harold L. Sirkin, a BCG senior partner, called the results “the latest evidence that a revival of American manufacturing is underway.”

The A.T. Kearney U.S. Reshoring Database, which holds roughly 700 reshoring cases that have been announced over the last five years, is forecasting only around 60 reshoring cases for 2015, a considerable drop from 2013 (210 cases) and 2014 (208 cases).

Patrick Van den Bossche, A.T. Kearney partner and co-author of the study, stated, "The U.S. Reshoring phenomenon, once viewed by many as the leading edge of a decisive shift in global manufacturing, may actually have been just a one-off aberration. The 2015 data confirms that offshoring seems only to be gathering steam, while the U.S. reshoring train that so many predicted has yet to leave the station."

Rising labor costs in China have not resulted in manufacturing returning to the United States, the study noted. Instead, operations in China have been moved to other Asian countries, such as Vietnam. U.S. imports of manufactured goods from Vietnam in 2015 will be nearly triple the level of imports in 2010. This shift to new low-labor-cost countries has been done without incurring significantly higher supply chain costs, despite their weaker infrastructure and supporting ecosystems, A.T. Kearney stated.

The consulting firm noted that the same search for cheaper labor is fueling the increase of nearshoring to Mexico.

The forecast strengthening of the dollar, the sharp drop in oil prices, the tightening U.S. labor market in manufacturing and the proposed Trans-Pacific Partnership (TPP) will likely further weaken the case for reshoring in 2016, A.T. Kearney stated.

While U.S. companies may not be rushing to reshore their operations, A.T. Kearney pointed out that non-U.S. companies, including Chinese companies, are investing in the United States. “The insatiable U.S. consumer market, the stable political and economic environment, and the benefit of tapping into America engineering skills and manufacturing know-how are main draws,” the firm stated.

Harry C. Moser, founder and president of the Reshoring Initiative, said a database maintained by his organization shows a smaller 40% reduction in reshoring activity rather than the 70% drop in the A.T. Kearney survey but "reshoring still at about twice the 2011 level." He argued that the A.T. Kearney survey does not actually measure reshoring but rather the trend in imports. And he pointed out that given that "the U.S. has one of the world’s fastest growing economies now, it tends to import more."

Moser also stressed that foreign direct investment and reshoring are "essentially the same phenomenon" and differ mainly in where the headquarters of a company is located. "In both cases the company decides it is more profitable to serve the U.S. market from a U.S.-based factory instead of from a foreign factory," he said.

“It is clear that about 25% of what is now offshored would be economically reshored today if companies used TCO (Total Cost of Ownership) instead of wage arbitrage or PPV (Purchase Price Variance) to make sourcing and siting decisions," said Moser. "A.T. Kearney would better serve its clients and country if it helped educate the companies rather than discouraging them.”