@techreport{blackridge_covariance_estimation_error_20260929,
  author      = {{BlackRidge}},
  title       = {{Historical Covariance Forecasts Underestimate Stress Risk by a Factor of 1.6}},
  institution = {BlackRidge},
  type        = {Research report},
  year        = {2026},
  url         = {https://blckridge.com/research/covariance-estimation-error-20260929/},
  note        = {Research synthesis. Original sources are credited in the report.}
}