As a senior finance editor, she has investigated companies involved with public-facing controversies, and is most widely known for her coverage of Tesla, Inc.[2][3] A regular contributor to Marketplace produced by American Public Media, Lopez teaches as an adjunct professor at the Columbia University Graduate School of Journalism.

[5] In 2020, she received the Excellence in Financial Journalism Award from the New York State Society of CPAs (NYSSCPA) for her opinion piece, “The Huawei indictment marks the end of US and China's cycle of trust”.

[3] According to Common Ground by Jane Whitney, which has featured Lopez as a panelist, her willingness to "[take] on titans in tech, politics, and business" ranging from Mark Zuckerberg to Donald Trump has made her the target of "intimidatory social media campaigns that have become all too familiar to 21st century journalists".

[4] At Insider, Lopez covered entrepreneur Elon Musk's businesses, exposing issues including alleged safety lapses at Tesla, Inc.[11][12] She also questioned the ethics and motivation behind some of his financial transactions, such as his 2016 bailout of SolarCity, a company founded by his cousins which had accumulated massive debt.

[13] In 2018, Lopez wrote that Tesla had stopped performing a brake test on its Model 3 electric sedan, in an effort to accelerate production at its assembly line, which had been fraught with problems.

[16][17] Although industry observers such as InsideEVs expressed skepticism because Lopez had chosen not to publish the two analysis reports written by external engineering firms which concluded that the aluminum used in manufacturing was prone to cracks, Russ Mitchell of The Los Angeles Times subsequently confirmed the claims in her Business Insider story after reviewing the contents of the emails and documents, and interviewing his own sources.