A worker monitoring the loading of containers on to a ship at the harbour in Qingdao, in northeast China's Shandong province.

Worries about the global economy percolate even as equities around the world rise, but an economist at Ned Davis Research says the worst of it may be over.

Alejandra Grindal, senior international economist at the firm, said the aggregate of manufacturing purchasing managers' indexes (PMIs) from across the globe stabilized in March after falling for 10 straight months. Meanwhile, the number of countries reporting expansion in the manufacturing sector rose for the first time in six months. She noted these indicators usually bottom about four to eight months "before the next expansion begins."

"We might be getting signs of a global economic recovery in the second half of the year," Grindal said at the Ned Davis Research annual investment conference in Boston. "At least it's sort of giving you some rays of light."

Grindal's comments follow the International Monetary Fund decreasing its 2019 growth outlook to 3.3%, which would be the lowest since the financial crisis, from 3.5%. In its report, the IMF highlighted risks such as the potential of increasing trade tensions as well as tighter monetary policy from the Federal Reserve.