When JPMorgan Chase & Co (JPM.N) consented to lead a $700 million [441.03 million pound] bond offering for Russian gas manufacturer Gazprom OAO, (GAZP.MM) it was doing business that some U.S. banks are afraid to do, several lawyers and also a banker said.

Gazprom faces U.S. sanctions after the united state federal government widened its restrictions against Russia in September. U.S. companies are restricted from offering goods or modern technology to Gazprom & others, although they could offer economic services to the companies, meaning JPMorgan obeyed with the law in underwriting bonds for the company. Gazprom announced pricing for the deal on Thursday.

Peter Kucik, a former U.S. Treasury official who left the division in March, said generally short-term transactions, such as underwriting bonds, should not be a problem. However he said U.S. companies need to make sure in conducting long-term business with Russian companies or Bank’s, because sanctions could possibly consistently get tougher in the future.

Some U.S. bankers would hesitate to do this business, fearing that also if it is legal, it will certainly look bad to regulators.

'Our relationship with regulatory authorities is so vital. We would not would like to make them mad,' said a capital markets banker at a competing firm. 'No one would certainly touch it with a 10-foot pole right here'.

Some banks' resistance to underwrite these sorts of bonds underscores the frostiness in relations between bank’s & their regulatory since the financial situation. Big banks globally face much tighter restrictions on their activity after the financial crisis of 2008 and have paid tens of billions of dollars in greats for violations over the past few years.

One lawyer who works extensively with sanctions issues said his clients are 'Skittish' & are reluctant to expend the effort to determine whether, as an example, underwriting bonds for Gazprom's would certainly be legal.

'They simply will not do business with the entities that are provided in those sanctions, also if it is legal,' the lawyer said.

It is unclear specifically just what JPMorgan did in this case, yet the bank usually checks in with regulators in advance of potentially sensitive assignments, such as through a phone call seeking an unofficial consent, a person acquainted with the issue said.

Doing the deal could help JPMorgan cement its connection with Gazprom, a company that the bank has collaborated with extensively in the past.

The U.S. sanctions against Russia are suggested to be surgical, focusing on particular people, sectors, and businesses, lawyers which deal with the sanctions said.