March 21 (Reuters) - S&P Global Ratings said on Thursday

its outlook for global grain merchant Archer-Daniels-Midland Co ( ADM )

was "negative", amid an ongoing investigation into the

company's accounting practices.

ADM's CFO, Vikram Luthar, was placed on administrative leave

in January as the company started a probe into the accounting

practices at its Nutrition segment.

In January, S&P placed the company's ratings on "creditwatch

negative" due to the investigation.

Last week, the company also confirmed some employees have

received grand jury subpoenas from the Department of Justice,

which is investigating its accounting practices. Reuters had

reported that FBI agents delivered subpoenas in Illinois.

The ratings agency on Thursday affirmed ADM's 'A' issuer

credit rating.

(Reporting by Arunima Kumar in Bengaluru; Editing by Devika

Syamnath)