Conversation so far:
What was the speculation regarding the presidential campaign with Michael Bloomberg?
Michael Bloomberg was frequently mentioned as a possible centrist candidate for the presidential elections in 2008 and 2012, as well as for governor of New York in 2010.
What was significant about Michael Bloomberg running for president?
According to a Washington Post article, Bloomberg's $500-million budget would allow him to circumvent many of the common obstacles faced by third-party presidential candidates.
Did Michael Bloomberg run for president?
Michael Bloomberg officially launched his campaign for the 2020 Democratic nomination on November 24, 2019.

Question: Who was speculating?
Self-contained rewrite: Who was speculating Michael Bloomberg's presidential campaign?