Relative cell reference in formula doesn't change as expected when copied to a different cell

I have a working IMPORTXML formula in Google Sheets that includes a relative cell reference. When I copy the formula to another cell, I expect the relative cell reference to update but it does not.

Here is my formula.

=importxml("https://finviz.com/quote.ashx?t=***AMZN&B3", "/html/body/div[3]/div[2]/div[4]/table/tbody/tr/td/div/table[1]/tbody/tr/td/div[2]/table/tbody/tr[3]/td[10]/b")

If the formula above is in O3. When I copy it down to O4 I expect the relative reference to B3 to update to B4.

What am I doing wrong?