(CNN)Add the co-founder of LinkedIn to those calling for Republican presidential nominee Donald Trump to release his taxes.
LinkedIn co-founder on Trump: 'The income tax doesn't lie'
"The income tax doesn't lie," Reid Hoffman told CNN's Erin Burnett on "OutFront" Wednesday night.
Hoffman is offering to donate up to $5 million if Trump releases his tax returns before the final presidential debate.
A vocal supporter of Democrat Hillary Clinton -- a woman he calls the most qualified political candidate of all-time -- Hoffman cited taxes as a clear window into a person's character and intentions.
"It's a question of whether or not there's conflicts of interest ... (the taxes) actually show you, what the person's actually like," he said.
Clinton has released several decades' worth of tax filings, but Trump has released none.