Loss run

Loss runs are the primary evidence of a risk's actual claims experience, and they carry disproportionate weight in pricing. Underwriters typically want three to five years of history, which means a single submission can include several loss runs from several different carriers covering different periods.

There is no standard format. Every carrier issues loss runs in its own layout, with its own column names, its own treatment of open versus closed claims, and its own conventions for reserves. Some are structured PDFs, some are scanned images, and some are spreadsheets. Merging them into one comparable history is a genuinely difficult data problem, and doing it by hand is where a large share of manual intake time is spent.

Errors here are consequential. A missed claim row understates loss experience and leads directly to a mis-rate, and the mistake typically only surfaces when a claim is disputed.