By Laura Matthews, Matt Tracy and Stefania Spezzati

NEW YORK/LONDON (Reuters) -Some bankers and traders are grappling with how to interact with Credit Suisse across various markets including debt and foreign exchange, with some increasing scrutiny when dealing with the Swiss bank or its products, sources said.

On Sunday, UBS offered to pay CHF 3 billion ($3.23 billion) for Credit Suisse, a hastily-agreed merger engineered by Swiss authorities following a scramble to save the bank.

Last week, at least four major banks restricted new trades involving the Swiss bank or its securities while Credit Suisse worked to restore investor confidence and stop its shares from plummeting.

That caution continued into this week. While most trading between banks is secured by collateral, one senior banker at a major bank in London said his bank had not resumed unsecured lending to Credit Suisse.

A leveraged finance banker was scrutinizing debt issuances that banker was an agent for to see if the debt issuances are affected by Credit Suisse, and said the bank had been ensuring there was not too much risk with involvement in any arrangements with Credit Suisse. The Swiss bank is still underwriting deals, the source said.

A source familiar with the matter also said the bank is still underwriting deals across asset classes, including leveraged loans.

A senior foreign exchange trader at a large bank in Europe told Reuters his bank was showing wider bid-ask spreads when dealing with Credit Suisse to compensate for the risk. Wider spreads increase trading costs.

The cautious approach shows bankers are still wrestling with the after-effect of the UBS-Credit Suisse takeover, concerned about what impact that could have on certain areas of the markets along with bankng sector turmoil.

Swiss authorities and UBS are racing to close the takeover within as little as a month, two sources with knowledge of the plans told Reuters on Thursday, to try to retain the lender’s clients and employees.

Since the latest banking sector problems began, banks have put much of their previously planned underwriting on hold until market volatility dies down, the leveraged finance banker said.

Others are also treading cautiously with Credit Suisse. On Monday a section of Bank of America halted trading with a desk at Credit Suisse that uses computer-led strategies “out of an abundance of caution.”

The senior FX trader told Reuters it still trades with the Swiss bank because the deal brokered over the weekend has restored confidence.

(Reporting by Laura Matthews, Matt Tracy, Stefania Spezzati; editing by Megan Davies, Nick Zieminski and David Gregorio)

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