Citi's Mark Shafir on the rise in SPACs and other 2020 dealmaking trends

M&A activity for the year has been notably down, but September has seen an uptick, particularly due to the rise of SPACs. Mark Shafir, Citigroup global co-head of mergers and acquisitions, joins "Squawk Box" to discuss the M&A space and what the rest of the year looks like