Market regulator, the Securities and Exchange Board of India, on Thursday said several companies were behind the recent leaks of quarterly results data on WhatsApp, PTI reported.

SEBI Chairman Ajay Tyagi said it was clear the companies had leaked the details themselves and warned of action against those responsible.

The market regulator began to investigate the leaks of company earnings in social media chatrooms in November after a Reuters report documented at least 12 cases of prescient messages about major Indian companies being posted in private WhatsApp groups. The messages involved upcoming quarterly results, net profits, revenues and operating margins and were circulated hours or days before the official company statements.

On December 22, SEBI conducted searches at properties owned by 34 market analysts and dealers in connection with its inquiry.

On Wednesday, it asked Axis Bank to improve its systems and conduct an internal probe to fix responsibility, as it said an initial investigation showed the information leak was a result of “inadequacy” of processes at the bank, The Economic Times reported.

At a press conference on Thursday, Tyagi said SEBI knew of more companies from where the leaks originated and said they will take necessary action. He also said the regulator would amend and strengthen the insider trading norms if required.

In 2015, India had toughened insider trading rules and expanded the scope of who constitutes an “insider” to include “anyone in possession of or having access to unpublished price-sensitive information”, regardless of how they came “in possession of or had access to such information”.

Circulating such information can lead to penalties and a jail term of up to 10 years.