By Gillian Tan 

After repeated attempts by U.S. regulators to curb lending for debt-laden takeovers, Wall Street banks are still taking divergent views on whether they need to pass on potentially lucrative deals.

Barclays PLC, Bank of America Corp., Goldman Sachs Group Inc. and Royal Bank of Canada's RBC Capital Markets have signed up to provide financing for one of the private-equity bidders vying to buy Swiss packaging company SIG Combibloc from Reynolds Group Holdings Ltd., according to people familiar with the matter.

Japan's Nomura Holdings Inc., which isn't subject to the U.S. regulatory push, also is onboard to finance the bidder, Onex Corp., one of the people said.

Citigroup Inc., Credit Suisse Group AG, J.P. Morgan Chase & Co. and UBS AG, meanwhile, are sitting out the deal on the advice of their internal monitors, concerned that it would earn them a black mark from regulators, according to people familiar with the banks' thinking. Morgan Stanley is also sitting out the deal, other people said.

At issue is a type of financing used by private-equity firms to take over corporations that could leave a company with a high level of debt that it may have trouble repaying.

The divide in the SIG deal highlights how banks differ on how to interpret guidance meant to rein in risky lending, even after regulators issued additional clarification this month.

The stakes are high for banks in the SIG deal in a year in which sizable private-equity buyouts that generate big fees for lenders have been relatively scarce. The SIG buyout is expected to value the company at roughly $4.5 billion, according to a person familiar with the deal. In a deal this size, fees could exceed $75 million.

"Part of the dilemma with these guidelines is that it's almost impossible to have a 100% agreement on every deal," a senior leveraged-finance banker said.

After an annual review of major banks' loan portfolios, the Federal Reserve, the Office of the Comptroller of the Currency and the Federal Deposit Insurance Corp. on Nov. 7 faulted banks for "serious deficiencies" in their leveraged-lending businesses and issued a list of frequently asked questions to clarify the guidance. The guidance, issued in March 2013, targeted leveraged lending.

Bankers said they rarely encounter a deal that would clearly pass muster with regulators.

The SIG deal is expected to leave the company, which makes milk cartons and juice boxes, among other things, with a debt ratio of about 6.5 times the company's earnings before interest, taxes, depreciation and amortization, or Ebitda, according to people familiar with the deal, which is at a level regulators generally view as risky.

The OCC has seen deals at that level that are acceptable, an official said last month, but added that buyouts above six times a company's Ebitda may attract "additional scrutiny and additional attention" and raise questions about the company's ability to repay its debt.

SIG, however, has sufficient cash flow that should enable it to repay the debt within the time frame preferred by regulators, according to people familiar with the deal. That has led some banks to deem it acceptable under their own internal guidelines.

Some banks have resisted regulators' push to curb such loans, which generate sizable fees, sometimes based on interpretations of what they called unclear guidance and other times concluding certain deals could move forward as exceptions. The guidance issued this month was supposed to make the rules more clear, but some bankers said they still aren't sure whether regulators will allow banks a limited number of exceptions, known as "bullets," each year. Others operate based on the understanding they have no exceptions.

"While intended to help banks interpret how to comply with the leveraged-lending guidance, the agencies have again declined to create any bright lines in the FAQs, leaving continued uncertainty about how to approach any given deal," said Jim Douglas, head of U.S. leveraged finance at law firm Freshfields Bruckhaus Deringer LLP.

The OCC has said it has a "no exceptions" policy on new loans. The Fed, on the other hand, expects disagreements among banks about individual deals. It has told the banks it regulates it is willing to accept such disagreements, so long as the bank is judging loans using an internal system that meets supervisors' expectations and that flags deals that fall clearly outside the regulatory guidance before those transactions get closed, a Fed official said last month.

The Fed regulates Credit Suisse, UBS, Barclays, Goldman Sachs and Morgan Stanley in this matter, while the OCC regulates the national banks housed at Bank of America, Citigroup and J.P. Morgan, along with RBC.

Big banks have been keeping track of how their rivals are approaching deals, watching to see if others are willing to put themselves in the regulators' firing line. Sizing up the competition with back-of-the envelope tallies of rivals' use of "bullets" can help them decide whether to attempt to take a bullet themselves, a complicated process with multiple internal hurdles, some bankers said.

The leverage-lending guidance appears to be deterring some banks from taking anything but a lead role on deals that could face regulatory scrutiny. Banks that don't get lead status are typically offered less significant roles to compensate them for the expenses attached to the pursuit of the deal. Some are shunning those nonlead roles to avoid tripping up the guidance on a deal that won't be lucrative for them, bankers said, and that could leave them in the red on some deals.

"Banks going through the process of risk committee want the fee opportunity to be meaningful and commensurate," said a managing director at a private-equity firm.

Simon Clark, Ryan Dezember, Mike Spector and Shayndi Raice contributed to this article.

Write to Gillian Tan at gillian.tan@wsj.com

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