The fact that the only rating published is ‘junk’, and that it was from a small agency tells us quite a lot. Given the fact that Anthropic (or its representatives) likely ‘shopped’ for a rating means that this was the best anyone was willing to give them, and that the larger agencies probably refused to rate them without more information. I would have been surprised if the bankers hadn’t lobbied for the highest rating possible, as higher ratings increase their profits from the IPO.