I don't think there is any built-in function that can access the formula in a cell.
If you want to go that route, you can use Apps Script function
My recommendation is that you adopt the following convention for yourself.
As much as possible,
always organize your data in two dimensions: each row is a new instance of your data type, each column is an attribute of your data type.
If you do that, you can easily apply Conditional Formatting, among many other things, based on column index. You can also apply Conditional Formatting based on the strings in the first row, ie. your header.
In your example, there should be 3 columns. Each column contains
ID/name of share;
share type (or a formula to output share based on the ID/name of your share);
and total received, which is a formula that computes your "total received" based on share type
You can use
arrayformula to apply your formula automatically and centralize your formulas in one cell. For example, in
=arrayformula(if(isblank(A2:A100,,ifs(exact(B2:B100,"Share Type 1"),A2:A100*0.8,
exact(B2:B100,"Share Type 2"),A2:A100*0.9))
B2:B100 or some relatively small number instead of
B2:B to reduce run time. The
isblank() check will ensure that the formula is only applied to the rows you entered share information on.
The custom formula for Conditional Formatting would be
=if(isblank(c2),false,exact(B2,"Share Type 1"))
C2:C for one color and duplicate the same thing for "Share Type 2" for another color.
There are a few things you can do in order to conveniently enter/output the type of the share. For example,
you can use Data Validation and then enter the type manually. Data Validation will help you enter the correct string every time and it also comes with a simple complete-what-you-type function;
or, if the type of a given share is fixed over time, you can have a list of all shares on a separate tab/sheet and each type of shares under a different column. Also enter the associated coefficients there using
arrayformula. Then use
vlookup on your main tab/sheet to retrieve those coefficients conveniently.