I don't know about poster, but offering COBRA isn't required for companies below a certain size. (I had to unexpectedly obtain private insurance to cover a gap

I don't know about poster, but offering COBRA isn't required for companies below a certain size. (I had to unexpectedly obtain private insurance to cover a gap in the pre-Obamacare era because the co I worked for only had a few employees.) It is a qualifying event for using the exchanges, but no idea about that being retroactive.