Final answer:
Mario's overall income subjects him to an additional Medicare tax usually applied to wages over a certain threshold. The exact additional tax can't be calculated as the threshold for 2023 is not provided, but it would be 0.9% of his income over that threshold.
Step-by-step explanation:
The student's question pertains to calculating the additional Medicare tax that Mario, who is single and earns wages of $440,000 in 2023, is obligated to pay. Based on the information that Medicare tax is generally at 1.45% of gross income with employers matching this rate, thus making the total Medicare tax 2.9%. However, for individuals with income above a certain threshold, there is an additional Medicare tax of 0.9%.
As of the previous years mentioned, there was no upper ceiling for Medicare taxes, which suggests that this likely remains the case in 2023. Considering this, Mario's income of $440,000 exceeds the threshold for the additional Medicare tax. To compute the additional Medicare tax, we should find the amount of income over the threshold (which has not been provided in the information but was $200,000 for individuals in previous years) and then multiply it by 0.9%. Without the exact threshold applicable in 2023, we cannot compute the precise additional Medicare tax amount for Mario.
It must be noted that the regular Medicare tax amount has already been covered by the 1.45% that is typically withheld from all of Mario's wages up to the threshold for the additional Medicare tax. The additional Medicare tax specifically refers to the extra tax due on wages above that threshold.