Jamie Dimon

On JPMorgan Chase’s third-quarter earnings call in October, Jamie Dimon bemoaned federal capital requirement regulations that prohibited his bank from stepping in to calm the repo market when it went haywire this fall—something that Dimon said JPMorgan “would’ve been happy to do.” Lo and behold, a few weeks later it emerged that none other than Treasury Secretary Steven Mnuchin had spoken with Dimon about the matter and had come to the conclusion that looser liquidity rules for the big banks may indeed be necessary. Perhaps it shouldn’t come as a surprise that the head of America’s largest financial institution holds such sway in matters of policy, but that’s exactly the kind of influence that Dimon has as he enters his 15th year at the helm of JPMorgan. For better or worse, he’s become the face of Wall Street—a figure of such recognition and renown that rumors of a presidential run refuse to go away. Beyond guiding JPMorgan to consistently positive results at a challenging time for the banking sector, Dimon has also shown a commitment to ideals beyond the bottom line. That includes his bank’s patronage of economic development programs in Detroit, as well as his role this past year in recalibrating the Business Roundtable’s statement of purpose to embrace serving a broader range of stakeholders. Don't miss the daily Term Sheet, Fortune's newsletter on deals and dealmakers.