For purpose of discussion, assume that due to bad luck, this asteroid has evaded the detection of all amateur and professional astronomers until about six months from impact. The asteroid is too large to deflect with humanity’s current spacefaring capabilities, and the general scientific consensus is that the impact will end all multicellular life on Earth.
What do those six months look like?
Who’s gonna be selling meteor insurance though? At that point all the CEOs will have said fuck you all and head to new zeland, leaving behind all the grunts