What caused StandardAero's tax expense spike in Q4 2024?

StandardAero's tax expense spike in Q4 2024 can be attributed to the following factors:

1. **Increase in Investment Taxes**: The most significant contributor to the tax expense increase was the recognition of a $32.69 million tax expense related to investment taxes. This suggests that there may have been a substantial amount of taxable gains or losses recognized in their investment portfolio during the quarter.
2. **Decrease in Investment Income**: The company experienced a decrease in investment income, primarily due to decreased investments in debt securities. This decrease could have led to a reduction in interest income, which in turn might have increased the relative importance of the investment taxes.
3. **Changes in Tax Regulations or Policies**: While not specified in the available information, changes in tax regulations or policies could have also contributed to the tax expense spike. Such changes could include updates to tax laws, regulations, or accounting standards that affect how companies calculate and report their tax liabilities.

In conclusion, StandardAero's tax expense spike in Q4 2024 was primarily driven by a $32.69 million tax expense related to investment taxes, coupled with a decrease in investment income and potentially changes in tax regulations or policies.