What caused T-Mobile US's operating profit spike in Q1 2023?

T-Mobile US's operating profit spike in Q1 2023 can be attributed to several key factors:

1. **Revenue Growth**: Total revenue for T-Mobile US in Q1 2023 was $20.12 billion, reflecting an 11% increase from the previous year. This growth in revenue contributes directly to an increase in operating profit.
2. **Cost Management**: The company's ability to manage costs effectively is crucial. In Q1 2023, T-Mobile US's operating income grew by 1.72%, indicating that the company was able to maintain profitability despite increasing revenues. This suggests that any increase in costs was offset by higher revenues, leading to a positive impact on operating profit.
3. **Subscriber Growth**: T-Mobile US has been experiencing significant subscriber growth, with 2.2 million total net additions in Q1 2023. This increase in subscribers contributes to higher revenue and profit, as each new subscriber brings in additional revenue without a proportional increase in costs.

In conclusion, T-Mobile US's operating profit spike in Q1 2023 is primarily driven by revenue growth and effective cost management, alongside strong subscriber growth.