Larry Fink, who leads the world's largest asset manager, said if Iran "remains a threat" and oil prices stay high it will have "profound implications" for the world economy.
The US financial giant and BlackRock boss has told the BBC, "If the price of oil hits $150 a barrel, it will trigger a global recession."
In a wide-ranging exclusive interview, he also denied there was an AI bubble, although he said the new technology meant too many people were pursuing university degrees and not enough doing technical training.
BlackRock is a financial colossus, controlling assets worth $14 trillion (£10.5tn), and is one of the biggest investors in many of the world's largest companies.
Its size and spread give Fink—who is one of the eight co-founders of the business, which started in 1988—a unique insight into the health of the global economy.
The conflict in the Middle East has triggered wild moves on financial markets as people try to assess what will happen to energy costs.
Fink expressed it is too early to determine the ultimate scale and outcome of the conflict, but he believes it will be one of two extreme scenarios.
In one, if the conflict is settled and Iran becomes a country that can be accepted again by the international community, then the price of oil could fall back to below where it stood before the war.
But if not, he says, then there could be "years of above $100, closer to $150 oil, which has profound implications in the economy" and an outcome of "a probably stark and steep recession."
