Chinese consumers may be staging an informal boycott of some American products and that could be a factor behind Apple's revenue shortfall, according to Bank of America Merrill Lynch economists. Others on Wall Street have made the same claim.

Apple last week stunned investors when it revealed its revenues would miss its forecast, in large part due to a drop-off in sales of its iPhone in China. Apple CEO Tim Cook laid the blame in big part on trade tensions, though Trump administration officials were at odds over whether the trade war was hitting U.S. companies doing business in China or whether Apple was its own case.

BofAML economists have said the sales shortfall could also be due to other factors, including competition, price and the drop in China's currency.

Ethan Harris, Bank of America Merrill Lynch chief global economist, said data on trade between China and the U.S. has been very clear and points to the potential of a consumer boycott. "I think what you see in the data is a broad pulling away from U.S. goods. If you look at the charts on imports, it's not just the products where there are tariffs by China. It's a general weakness in imports," he told CNBC.

China rebuked the U.S. for tariffs last fall by reducing orders of soybeans. On Tuesday, as trade talks were underway, there was a seeming thaw in relations. China approved five genetically modified crops for import, the first in 17 months. Some of the products have been waiting for approval for six years, according to wire reports.

While Chinese purchases of U.S. soybeans dropped, there was a clear pickup in Chinese imports from Brazil. "The soybean story is a big part of it. That was something we all expected. It's the broad-based drop that looks unusual and surprising, particularly since it isn't replicated with other countries," said Harris.

Analysts have said the tensions between China and the U.S. over the U.S. pursuit of alleged cyber-espionage by Chinese telecom companies may also be a factor. The CFO of Huawei has been arrested in Canada and may be extradited to the U.S.

U.S. authorities allege CFO Meng Wanzhou deceived international banks into clearing transactions with Iran by claiming the two companies were independent of Huawei, when in fact Huawei controlled them.

"There may be some consumer backlash to American companies, a form of nationalism," said Bernstein analyst Toni Sacconaghi on CNBC last week. But he said there are many things at work with iPhone sales, including a weaker upgrade cycle and the macro picture of a weaker China.