When Cotterell Mitchell & Fifer Insurance (CM&F Group) was founded in Manhattan in 1919, the company was made an offer that it decided it could refuse- the opportunity to buy the office building it then occupied, reports Bruce Sinder, president of Sinvin Realty Corp.But in 2003, CM&F Group, realizing that their subsequent rent expenditures all these years was enough to have bought that building many times over, have become owners.The malpractice insurer for doctors, dentists and nurses has purchased unit #12A of 99 Hudson Street for $2.7 million. Porter Fulmer, a broker with Sinvin Realty Corp., arranged the transaction. Herman W. Hertweck of Williamson, Picket, Gross, Inc. represented CM&F Group. 99 Hudson Street is a 17-story building built in 1930.The seller was Steven J. Massarsky, President and Founder of B.I.G. (Business Incubation Group) who purchased the property in 1999, prior to the current boom in commercial office condos. Sterling National Bank provided financing for the buyer.