Risk.net
Star quant proposes a new model for predicting changes in bond ratings
Richard Martin speaking with Mauro Cesa
Photo: Monika Ghose
Risk.net’s Cutting Edge pages.
Martin discusses his most recent paper,
Credit migration: generating generators, in which he proposes improvements to classic Markovian models.
Credit migration describes the evolution of upgrades and downgrades of bond ratings. It is commonly modelled using a matrix of parameters, known as generator matrix. But this approach has a known problem: a large number of parameters can lead to an unstable calibration, potentially making it difficult to identify the optimal solution.
Risk.net
Risk Awards 2021: credit specialist proved its worth in the Covid crisis
Boaz Weinstein
In late 2019, Boaz Weinstein was seeing mispricings in credit markets on a scale he’d never seen before – the kind of twisted values that meant spreads on Sabre, a newfangled travel-tech company, were the same as for a solid credit like fast-food chain McDonald’s.
“In my career, I had never seen such a tight packing between double-Bs that you would want to short and single-As you’d want to go long,” he says.
By the end of the year and in the opening weeks of 2020, one of the main trades at Weinstein’s Saba Capital Management was to short a basket of riskier high-yield credits and go long a basket of quality names. “The market allowed you to do that basically for zero cost,” he says.