Christie to Romney: Open up Gov. Chris Christie (R-NJ) endorses Republican presidential candidate Mitt Romney during a rally at Exeter High School in Exeter, New Hampshire on Jan. 8. Christie says Mitt Romney should loosen up and let the American people "see who Mitt Romney really is." TRENTON, N.J., July 3 (UPI) -- Outspoken New Jersey Gov. Chris Christie says Mitt Romney should loosen up and let the American people "see who Mitt Romney really is." Commenting on the presumptive Republican presidential nominee's known reserved style, Christie told ABC News he believes Romney knows he needs to be more open. I think as time progresses in this campaign, you're going to see him open himself up more and more to the American people, and let them see who Mitt Romney really is, like I've had the opportunity to see. And I think when they do, they're going to like what they see," Christie said during an interview that airs Tuesday. Christie, considered a contender on Romney's short list of running mates, didn't deny he turned over paperwork or his personal documents to the Romney campaign, saying any "phone calls between me and Mitt Romney are between me and Mitt Romney." "I think any of that stuff is up to the Romney campaign to talk about and not up to any of the individual people who might be being vetted to discuss," Christie said. Christie said he'd talk to Romney if the former Massachusetts governor calls. "He's the nominee of my party, and if he calls and he wants to talk about that, I'll talk to him about it," Christie said. But that's up to him, not up to me. Of the four lawmakers considered on the short list, personal financial disclosure forms indicate Sen. Rob Portman of Ohio is the wealthiest, Roll Call reported Tuesday. He had a minimum net worth of $6.72 million at the end of 2011. Sen. Marco Rubio of Florida likely is among the least wealthy senators, with a net worth of negative $400,000, financial documents indicated. Documents indicated Rubio had at least $127,000 in rental property, retirement funds and other assets, but they were offset by at least $100,000 in student loans, at least $350,000 in mortgages on his personal home, and a mortgage of at least $100,000 on a Tallahassee rental property. Rep. Paul Ryan of Wisconsin, chairman of the House Budget Committee, has a minimum net worth of $1.9 million, Roll Call said. Financial disclosures indicated Sen. John Thune of South Dakota, who backed Romney's bid early-on, has a minimum net worth of $57,000.