We switched from an Inc to an LLC a few years back and were advised by the lawyers and CPAs to keep the existing contracts under the Inc and have all the new contracts under the LLC. This means you have to keep two sets of books until all your existing contracts are closed out but it made the transition clean. I know the overlap isn't clean on paper and honestly a bit of pain but that was how we were advised and how we did it.
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Daniel Shaffer, AIA
CMSA, Scholz, Oswald & Shaffer LLC
Sarasota FL
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