Lehman Brothers has approached other major financial institutions, and is receiving assistance from the U.S. Treasury, on a potential acquisition or investment in the battered securities firm, people close to the situation said Thursday.The nation’s No. 4 investment bank has been casting a wide net to find a potential buyer for all or part of the 158-year-old firm, bankers and executives at other financial companies said Thursday. The bankers and executives asked not to be named because they are not authorized to comment publicly.The Treasury is looking at several options for resolving Lehman’s dilemma, but has not arrived at a deal or solution that it is prepared to announce this weekend, as some news sites have said.Randy Whitestone, a spokesman for Lehman, declined to comment.Bank of America Corp., France’s BNP Paribas, Deutsche Bank AG and Britain’s Barclay’s Plc have been mentioned this week as potential buyers of Lehman, which Wednesday outlined a plan to sell and spin off assets to raise money.The bankers and executives said Lehman’s leader, Richard Fuld, also has been stepping up talks with private equity firms such as Kohlberg Kravis Roberts & Co. and Bain Capital to acquire its investment management division that includes Neuberger Berman.Lehman Brothers Holdings Inc.’s shares tumbled again on Thursday after its rescue plan got a dismal reception from Wall Street and analyst reports cast doubt that the nation’s fourth-largest investment bank can survive.Its shares fell $3.03 to $4.22 [-] down nearly 94 percent from their 52-week high of $67.73.On Wednesday, Lehman Brothers outlined a blueprint to sell off its well-respected investment management unit and spin off its commercial real estate assets. The strategy is part of a last-ditch effort to rescue the investment bank from bad bets on real estate-related holdings that have already laid low other storied Wall Street firms.Lehman Chief Executive Fuld, 62, the longest-serving CEO on Wall Street, also said the firm would examine all other options — including a sale of the company he joined right out of college.Analysts said investors had hoped to see a solid plan in place to offset almost $6.5 billion of losses during the past two quarters.“Management did not successfully put to rest the issues that had been pressuring the stock,” Goldman Sachs analyst William Tanona wrote in a research report.Lehman said Wednesday it plans to sell a 55 percent stake in its investment management division, which includes its prized Neuberger Berman asset management unit.Investors were discouraged that no specific buyer had been named. Lehman began pitching a deal to private-equity firms two months ago. Analysts believe the sale could fetch about $3 billion.Further, the firm is also taking a big bet that a spin-off of its commercial real estate assets will get a strong market reception in early 2009. The new entity will be called Real Estate Investments Global, and will be run by independent management.Wall Street remains skittish about financial stocks since a run on Bear Stearns caused the U.S. government to orchestrate its sale to JPMorgan Chase & Co. in March. Lehman, the biggest U.S. underwriter of mortgage-backed securities, was automatically scrutinized.Global banks have lost more than $300 billion from write-downs since the housing slump evolved into a full-blown credit crunch.Analysts believe that trying to engineer a reconstruction of Lehman Brothers will be a tough proposition considering the environment. The current financial crisis shows no sign of ending soon, credit conditions remain tight and big acquisitions are rare. Big institutional investors — like state-owned sovereign wealth funds and private-equity firms — aren’t as willing to make major investments.This story is based in part on wire service reports.