But the feisty self-described democratic socialist has nevertheless refused to concede defeat to his more moderate rival, though he has said he will vote for Clinton and will do anything to help defeat Republican Donald Trump.
But Sanders' supporters made clear they wanted changes.
In a two-way contest, 51 percent of registered voters support presumptive Democratic presidential nominee Clinton or lean towards her while 42 percent support or lean towards presumptive Republican presidential nominee Trump, Pew Research Center said in its latest survey yesterday. "Sanders has been on record that one of the issues that he and Secretary Clinton were interested in exploring further was how to make health care available to more Americans".
Sanders openly confirmed there were talks about an endorsement giving a public voice to private talks that have been going on for three weeks. Clinton's "College Compact", which aims to create a more affordable path to higher education for all students, doesn't quite adopt the Vermont senator's goal of free higher education across the board, but it definitely makes moves in that direction.
Although Sanders has promised to vote for Clinton in the general election, he has not endorsed her or campaigned on her behalf.
What will be interesting, in the opinion of this author, is to see if Bernie Sanders will use the opportunity on July 24 to speak to his supporters and ask them to endorse Hillary Clinton... or will he will surprise everyone with information about potentially becoming the Democratic nominee?
"He ran a remarkable campaign; he didn't win", said Bob Shrum, a longtime Democratic strategist and politics professor at the University of Southern California.
Some Democrats have grown tired of Sanders' apparent reluctance to back Clinton, and a group reportedly booed him during a closed session with the House Democratic caucus Wednesday morning after he wouldn't answer questions about when he would endorse her. Barack Obama, Clinton ended her presidential bid and endorsed him in a speech on June 7.
Still, Sanders has sought more going into the Democratic National Convention's full platform committee meeting in Orlando.
Sanders has said he will vote for Clinton and that he will work to defeat Trump.
Clinton's joint appearance with Warren - their first of the campaign - was viewed by many as an audition for the ticket.
The current draft of the platform shows Sanders' influence, as it endorses steps to break up large Wall Street banks, advocates a $15 hourly minimum wage and urges an end to the death penalty.
Bernie Sanders will continue to campaign in July and is planning to hold a rally with supporters before the Democratic National Convention on July 24 in Philadelphia.