Bankers are set to launch the biggest commercial-real-estate debt deal since the financial crisis began, people familiar with the matter said. The offering will allow two Wall Street firms to sell loans tied to the boom-time buyout of Hilton Worldwide and signals a thawing in one of the most troubled financial markets. The $3 billion offering is expected to be followed by a $2 billion deal involving the Extended Stay Inc. hotel chain that recently exited bankruptcy, people familiar with the transactions said. Together, the deals would be by far the largest issuance of commercial mortgage-backed securities, or CMBS, since the downturn and the most vivid sign to date of a resurgent CMBS market. The Hilton deal stems from Blackstone Group LP’s $26 billion purchase of the hotel chain in October 2007. Banks, including Goldman Sachs Group Inc. and Bank of America Corp., provided $20 billion in financing but were stuck holding the loans when debt markets froze. The sale, expected in the next two weeks, will allow the two banks to sell the $3 billion in senior debt they still hold. The offering likely will leave the banks whole on their investments, which few would have predicted during the crisis when the loans were trading as low as 70 cents on the dollar, people familiar with the matter said.