NEW YORK (Reuters) - BlackRock Inc Chief Executive Larry Fink expects stocks to keep rallying in 2021, he told Reuters on Thursday. With global interest rates low there is a great need for long-duration assets, including from pension funds, and public equities still remain the most opportunistic way to invest those, the head of the world’s largest asset manager said. BlackRock Inc’s quarterly results topped analysts’ expectations on Thursday, buoyed by a rising stock market that boosted the firm’s assets under management to a record high $8.68 trillion, further widening its lead against peers. Fink said he is closely monitoring the progress of vaccinations against COVID-19 for clues to when sections of the economy that have been hard-hit by the pandemic may bounce back. “Most probably by the third quarter, definitely by the fourth quarter, we are going to see parts of the economy that are still struggling are going to start rebounding,” Fink said. Economists forecast U.S. growth will lose momentum in the first quarter but accelerate at a faster-than-expected pace later in the year. A majority now believe the economy will reach pre-COVID-19 levels within a year, a Reuters poll from December showed. While there may be pockets of the market where valuations may be stretched, overall, there are opportunities in the global market, Fink said. “If you believe that the dollar is going to be weakening because of the set of new fiscal stimulus, you could be investing globally with a little bit more confidence,” he said. U.S. interest rate cuts and the prospect of further fiscal stimulus under the incoming Biden administration are expected to weigh on the dollar, which is down about 7% against a basket of currencies, from a year ago. President-elect Joe Biden will unveil a stimulus package proposal on Thursday designed to jump-start the economy during the coronavirus pandemic with an economic lifeline that could exceed $1.5 trillion. The stimulus package is expected to include $1,400 stimulus checks. “There is stimulus and there is stimulus... I want to see the composition of this stimulus,” said Fink. If the stimulus is just a fix for those that are unemployed, it will have a very short lifetime, he said. Stimulus that is heavily oriented toward infrastructure would have a more lasting impact and be a huge job creator, Fink said.