# Calculate outstanding diluted shares for fourth financial quarter of a company

How would one calculate the correct value of the outstanding diluted shares for the fourth (last) financial quarter of a company?

When using the SEC 10-Q and 10-K forms: The 10-Q forms contain the number of outstanding shares that are specific to the quarter (Q1 to Q3). The 10-K form contains the number of outstanding shares that are specific to the whole financial year.

How would I now calculate the number of outstanding shares that are specific to the fourth quarter?

Example for AAPL (values from 10-K and 10-Q SEC):

• Q1 (10-Q), ending on 2019-12-28 reported 17.818.417.000 outstanding diluted shares
• Q2 (10-Q), ending on 2020-03-28 reported 17.618.765.000 outstanding diluted shares
• Q3 (10-Q), ending on 2020-06-27 reported 17.419.154.000 outstanding diluted shares
• Annual report (10-K), ending on 2020-09-26 reported 17.528.214.000 outstanding diluted shares

What is the amount of outstanding diluted shares when viewing Q4 isolated? I found two different examples: https://stockanalysis.com/stocks/aapl/financials/ Here they display 17.256.516.000 as value for Q4 - although I don't get how they calculated it. Another example is this: https://www.macrotrends.net/stocks/charts/AAPL/apple/shares-outstanding Here they display the same value as the annual 10-K report, so 17.528.214.000 for Q4.

What is the 'correct' way to do this? Is there even a correct way to do it?

I was wondering about it because depending on the calculation of the outstanding shares the value of EPS (and others) may differ.

$$\frac{17.818.417.000 + 17.618.765.000 + 17.419.154.000 + 17.256.516.000}{4} = 17.528.213.000$$