Lyttleton, who left the group in March 2013, admitted dealing in the basis of insider information he obtained during his time working at BlackRock.
He was summoned before the City of London Magistrate's Court in September 2016 on three counts of insider trading.
As well as being lead manager on BlackRock’s UK Dynamic and UK Absolute Alpha funds, he also held a role in the fundamental equity team at BlackRock.
Lyttleton was either party to conversations about, or involved in deals pertaining to, EnCore Oil – between 1 October 2011 and 13 October 2011, and Cairn Energy – between 4 November 2011 and 17 December 2011.
As such, he was able to use the inside information to inform his purchase of shares shortly before any public announcement was made about the stocks concerned.
He conducted his trades through an overseas asset manager trading on behalf of a company registered in Panama.
The case was heard at Southwark Crown Court.