Pitchbook for company out of core space

I do not want to go into detail in order to remain anonymous, but I started at a boutique that did M&A in one sector and occasionally branched out into a related sector.

You should put together a similar pitchbook as you would for other pitches. The only difference is that it's going to be a PIA to put together the industry slides. Hopefully your bank has access to some research data base or senior bankers willing to assist. You will want to also highlight your bank's overall experience more. You might not have experience in this sector, but you probably have some experience in plenty of others. So, choose tombstones in similar sectors/companies of similar size, include a few extra MDs in your banker profile page, etc.

Also, have you asked your senior bankers for guidance? They obviously won't create the pitchbook for you, but they might have a general idea of where to start.

I hope that helps. Good luck.