April 28 (Reuters) - The following bids, mergers,

acquisitions and disposals were reported by 0930 GMT on Tuesday:

** Activist investor Starboard Value has taken a major stake in

AI software maker Dynatrace ( DT ) and is advocating for

strategic changes to help boost its share price, the Wall Street

Journal reported on Monday, citing a draft of a letter by a

senior executive.

** Brazilian state-run firm Petrobras announced on

Monday an agreement to acquire a portion of the Argonauta oil

field's ring-fence in the Campos Basin for some $290 million.

** Investment firms Stonepeak and Bernhard Capital said on

Monday they will acquire Louisiana electricity supplier Cleco

Group for an undisclosed value from a consortium that includes

Macquarie Asset Management.

(Compiled by Rajarshi Roy in Bengaluru)