Fidji Simo, the No. 2 executive at OpenAI, announced on Thursday she is stepping down from her full-time position to focus on her health, stating she had to go on medical leave "three months ago" after "a severe exacerbation of a chronic illness I've lived with for seven years." Simo wrote that the road to recovery "would be much longer and more complex than I had anticipated," and she will continue working for the company as a part-time adviser. The announcement comes as OpenAI is preparing to go public and facing stiff competition from rival Anthropic, and Simo was expected to assume a more prominent role following the initial public offering, according to The Wall Street Journal.