Age: 61
Occupation: Consumer advocate and Obama Administration adviser
Previous TIME 100 appearances: 2
Elizabeth Warren is only the acting head of the newly formed Consumer Financial Protection Bureau, but you wouldn't know it from her busy agenda. In her temporary job, she has played a significant role in pursuing mortgage servicers for processing abuses, has forced banks to divulge information on credit-card fees and has started to write new rules on home loans. And this is all before the CFPB, which is supposed to regulate financial products much as the Food and Drug Administration oversees medicines, officially opens for business in late July. If Warren gets the permanent job — consumer advocates and newspaper columnists around the U.S. have lobbied for her, but some Republicans and many financial executives oppose her because they think she would be too tough on the banks — she would be the most powerful new banking regulator in decades.