2019–2020 Karvy Stock Broking — SEBI/NSE action over pledge/misuse of client securities (~95k clients cited in press)
Data compromised
Client securities positions and brokerage relationship metadata in supervisory narratives
Technical writeup
Nov 2019 SEBI ad‑interim action and subsequent depository/clearing remediation focused on Karvy misuse of client demat pledging to raise group financing—a custody and control failure often bucketed with market‑integrity “breach of trust” even though it is not a classic database ransomware attack.
Root cause
Unauthorized use of client assets / control breakdown at broker layer