Credit to the private non-financial sector as a share of GDP, minus its long-run trend. The BIS publishes it as the early-warning indicator behind the Basel III countercyclical capital buffer.

Threshold source: Basel Committee guidance: a gap above 10 pp calls for the maximum countercyclical buffer. How thresholds are chosen

The trend is a one-sided filter and is revised as new quarters arrive. Deeply negative gaps after a crisis persist for years and say little about current risk.