Former US Congressman Stephen Buyer has been charged with insider trading over purchases of shares in telecommunications company Sprint before it merged with T-Mobile US Inc, prosecutors said on Monday. Buyer, a Republican who represented Indiana in Congress between 1993 and 2011, was working as a consultant to T-Mobile ahead of the 2018 merger, according to an indictment filed by federal prosecutors in Manhattan. Prosecutors said he used non-public information he learned through his consulting work to buy 112,675 Sprint shares in four brokerage accounts ahead of the April 29 merger announcement, earning a profit of about $126,000. The next year, Buyer allegedly generated $223,000 in profit trading in professional services firm Navigant Consulting Inc after learning non-public information it would soon be acquired by Guidehouse, his consulting company, prosecutors said. Buyer faces four counts of securities fraud over the alleged deals, and related civil charges from the US Securities and Exchange Commission. A lawyer for Buyer could not immediately be identified. Damian Williams, the top federal prosecutor in Manhattan, was expected to address the charges against Buyer and six other individuals in four unrelated insider trading cases later on Monday. Williams, an appointee of President Joe Biden, has made combating financial crime a centrepiece of his agenda. In April, federal prosecutors in Manhattan announced fraud and racketeering charges against Bill Hwang related to the meltdown of Archegos Capital Management, the private investment firm he founded. In May, Williams’ office reached a $6b settlement with Germany’s Allianz SE over the collapse of investment funds run by the firm’s US asset management division.