Since the authorities opened the investigation into JPMorgan last spring, the inquiry has entangled other Wall Street giants. Citigroup, Credit Suisse, Deutsche Bank, Goldman Sachs, Morgan Stanley, UBS and other banks have received requests for information, according to people briefed on the investigations.
The banks declined to comment on the investigations, which are at an early stage.
S.E.C. officials and the prosecutors also declined to comment.
Banks are not prohibited from hiring the family and friends of Chinese officials. A hiring would be a violation of the Foreign Corrupt Practices Act only if it can be shown that a bank explicitly swapped job offers for business deals with Chinese government officials. Such a bank must also have operated with the "corrupt intent" to influence a Chinese official, a blurry line that might be crossed if unqualified employees were hired.
The applicant who met Mr. Dimon is well educated. She had a graduate degree from New York University. At JPMorgan, she received strong performance reviews.
Mr. Evangelisti, the bank spokesman, said that the applicant had "prior experience serving as an interpreter" before the meeting with Mr. Dimon and Mr. Xiang.
(Read more: Judgeallows JPMorgan to settle Madoff lawsuits for $543M)
Even if federal authorities decline to pursue a case against the bank, JPMorgan's hiring practices could also raise concerns with the authorities in Britain and Hong Kong, where anti-bribery laws are stricter than the Foreign Corrupt Practices Act in the United States. The authorities could focus on the bank's "Sons and Daughters" hiring program, in which well-connected applicants routinely face fewer interviews and special treatment.
The daughter of a top executive at Tianhe, a private Chinese chemical company, received some extra attention after her father called JPMorgan to complain that her contract did not stack up to other JPMorgan employees, according to a previously unreported email reviewed by The Times. Her contract, he said, was not permanent and lacked a housing allowance.
The complaint arrived soon after the young woman joined JPMorgan in 2011. At that time, the bank was seeking an advisory role on Tianhe's initial public offering of stock.
"It sounds to me like the deal is large enough, we are pregnant enough with this person, that we'd be crazy not to accommodate her father's wants," a JPMorgan executive in Hong Kong wrote in the email.
(Read more: Sen. Warren blastsCEO Jamie Dimon's big raise)
Recently, JPMorgan withdrew from the potential $1billion I.P.O. of Tianhe. A spokeswoman at a Hong Kong public relations agency representing Tianhe declined to provide a statement from the company.
Asked recently on CNBC about abandoning the deal, Mr. Dimon said, "I don't know the circumstance exactly, but I think we're trying to make decisions that try to make us as pure as possible, that we're trying to do the right thing."
Mr. Dimon played down the significance of hiring well-connected applicants. In the interview with CNBC, he said "it's been a norm of business for years that people hire, you know, ex-government officials,they hire sons and daughters of companies, and give them proper jobs and don't violate, you know, American Foreign Corrupt Practices Act."
JPMorgan started its Sons and Daughters program in2006, somewhat early in Mr. Dimon's tenure at the bank. Six years later, when hemet with Mr. Xiang, the nation's top insurance regulator, some of China's biggest insurance companies were planning to go public. Around that time, JPMorgan was vying for roles on these deals — some of which it secured.
Since Mr. Dimon's June 2012 meeting with Mr. Xiang, JPMorgan advised the AIA Group on three separate deals, according to Thomson Reuters and Standard & Poor's Capital IQ, a research service. It is unclear whether the assignments were in the works before the meeting. AIA, a Hong Kong-based insurance company, had worked with JPMorgan on at least three deals before the meeting. During some of those deals, AIA was owned by the American International Group, the giant New York-based insurer.
The People's Insurance Company of China, a state-owned insurer, also hired JPMorgan as one of 17 banks for its November 2012 I.P.O. That same month, JPMorgan was the co-lead underwriter on China Taiping Capital Ltd.'s $297 million debt offering, according to Capital IQ. The holding company of China Taiping again picked JPMorgan as an adviser when the insurer acquired stakes in a number of subsidiaries last May.
For Wall Street, one of the most coveted insurance deals was the I.P.O. of Taikang, often listed as the fifth-largest insurer in China. In a 2011 email reviewed by The Times, a JPMorgan banker referred to the"juicy size" of the deal.
For now, it is unclear whether JPMorgan secured arole on the I.P.O., which has not been publicly announced. But to bolster its chances with Taikang, JPMorgan had a plan: hire the "direct niece of chairman."
"Link to ipo," another banker said in a separate 2011 email, "is very direct."
—By Jessica Silver-Greenberg and Ben Protess of The New York Times