Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

In December 2014, investors who had purchased American Depository Shares (ADSs) of Petrobras on the New York Stock Exchange filed a securities class action in the Southern District of New York, alleging violations of the Securities Act of 1933, the Securities Exchange Act of 1934 , and (in an amended complaint) Brazilian securities laws.

Answer: stock_exchange: Petrobras, New York Stock Exchange