Back in October 2025, a situation unfolded where more than 600 employees of OpenAI took the opportunity to sell shares, with the total value of these sold shares reaching around $6.6 billion. This sale occurred against the backdrop of the company being valued at a staggering $500 billion. In English business - related reporting, it's common to provide such context - rich descriptions. By adding "Back in" at the beginning, it gives a sense of looking back at a past event. Also, rephrasing "sold approximately $6.6 billion worth of shares" to "took the opportunity to sell shares, with the total value of these sold shares reaching around $6.6 billion" makes the sentence more natural and detailed, following the English habit of building up information step - by - step. And explaining that the sale happened "against the backdrop of the company being valued at..." helps readers better understand the circumstances of the share - selling event, which is a common way of presenting business news in English to enhance comprehensibility.