I work for a company that shares office space with Sigma. They did have a few issues with funding a couple of weeks ago, but that has all been sorted out now and they are up and running again.
Saxon have changed their model and are no longer an arcade - more of a hedge fund.
Don't know about Schneiders, but believe they are still going.
Don't know how all these rumours start - someone I know phoned me about Sigma the day it happened and knew before me despite me being able to see into their office and them being about half a mile away!