Jamie Dimon (Giulia Marchi/Bloomberg News)

Jamie Dimon, chief executive of JPMorgan Chase, is the latest and one of the most high-profile business executives to drop out of a Saudi investment conference in Riyadh this month, after allegations that Saudi agents killed the dissident journalist Jamal Khashoggi.

A spokesman for JPMorgan confirmed Mr. Dimon “is no longer attending” the event. He declined to say why or to comment further.

In what could be an even bigger withdrawal from the event, Treasury Secretary Steven Mnuchin is weighing whether to attend — after saying last week he did plan to go.

“We will evaluate the information that comes out this week,” a Treasury spokesman said Sunday.

Dimon follows nearly a dozen other executives from the technology, media and entertainment industries who have backed out of the Future Investment Initiative conference, nicknamed “Davos in the Desert.” Many of those business leaders have cited Khashoggi’s alleged killing inside the Saudi Consulate in Istanbul this month as their reason for backing out.

The relationship with Saudi Arabia is important to Wall Street executives like Dimon because the country is a major investor around the world and does significant business with Western financial firms. Saudi Arabia, for example, has hired JPMorgan and other big banks to help it sell government bonds in recent years. Western banks have also hoped to help the kingdom privatize its giant oil company, Saudi Aramco, although the country’s plans for an initial public offering appear to have stalled.

It is not clear whether decisions by Dimon or other financial executives about attending the conference will have any longer-term consequences for the business relationships between the oil-rich nation and Wall Street firms. A decision by Mnuchin not to attend would be a rebuke by the Trump administration of the Saudis, although whether it would be accompanied by other punishments is not clear.

The Saudi conference is part of Crown Prince Mohammed bin Salman’s effort to modernize the kingdom’s economy and diversify it away from oil. The crown prince has also promoted other projects meant to attract more foreign investment to the country, including the NEOM project that aims to build a tech and tourism hub in the northwestern corner of the country.

Western tech-industry officials have backed away from NEOM in the wake of Khashoggi’s alleged killing. Sam Altman, president of start-up investment firm Y Combinator, said last week he was suspending involvement with NEOM’s advisory board “until the facts regarding Jamal Khashoggi’s disappearance are known.”

On Thursday, a spokesman for Dan Doctoroff, chief executive of Sidewalk Labs, a sister company to Google, said NEOM had been “incorrect” to include Doctoroff on its list of advisory board members. Doctoroff “is not a member” of the board, the spokesman said.

The Turkish government has told U.S. officials that it has audio and video recordings proving that Khashoggi was killed inside the Saudi Consulate in Istanbul this month. Saudi officials have denied any involvement in Khashoggi’s disappearance, saying he left the consulate shortly after entering.