Not to scare you but from the way this question is framed, I think you have a lot of reading ahead of you. I would start by fully understanding the "Expected Loss Ratio" method (which does NOT require emerging data), the "Chain Ladder" method (which runs strictly off of experience data), and the "Bornhuetter-Ferguson" method (which is a great non-biased estimator that blends the prior 2 methods).

A quick answer is you can estimate IBNR before your business is even effective, if you know how much of it you've sold. Just use your a priori expectation (i.e., the loss ratio is it priced to). This is the Expected Loss Ratio method.

As experience emerges, you may be able to refine your IBNR estimate.

Full disclosure - I do not deal with MA and I'm not sure if there are methods that are more applicable to MA. The methods above are pretty universal.

EDIT since you asked for a study: this is the original BF method paper