S&P Global Ratings lowered its outlook on three Adani Group entities to 'negative' from 'stable' on Friday, citing risks to funding access following a U.S. indictment of the conglomerate's billionaire founder, Gautam Adani, on bribery charges.

Adani and seven other people, including his nephew Sagar, were indicted on Thursday for fraud by U.S. prosecutors for their alleged roles in a $265 million scheme to bribe Indian officials to secure power-supply deals.

Adani Group has said the accusations levelled by U.S. federal prosecutors, as well as those by the U.S. Securities and Exchange Commission in a parallel civil case, are "baseless and denied" and that it will seek "all possible legal recourse."

The U.S. indictment could affect investor confidence in other Adani Group entities, as the founder sits on the boards of other companies within the group, potentially impairing their access to funding and increasing funding costs, S&P said in a note.

"The group will need regular access to both equity and debt markets given its large growth plans, in addition to its regular refinancing. We believe domestic, as well as some international banks and bond market investors, look at Adani entities as a group and could set group limits on their exposure," S&P said.

S&P revised the outlook on a unit of Adani Green Energy , the entity linked to the allegations, to 'negative' from 'stable'.

Adani Electricity and Adani Ports were also downgraded to 'negative', S&P said, adding that ratings on the three entities could go lower if allegations are proven true.

Cash flows of the group entities are expected to be materially affected due to an anticipated weakness in funding access, S&P added.

Bonds and most stocks of the Adani Group dropped for a second session on Friday after the indictment.