Is there any rule, in any style guide, that would allow a comma to be placed after "capabilities" as shown below? Client wants to leave as is, and I'm trying to find a way (in my own mind) to be okay with this.

Within the reporting product, there may be some drill-down capabilities, but usually not full pivot and ranking capabilities.

There is a lot of leniency on this subject, and a comma is easily justified.

Within the reporting product, there may be some drill-down capabilities,

[because the next section contains 'and', I think the comma is useful to partition the sesction and to show that it all falls under the influence of 'but']

but usually not full pivot and ranking capabilities.

Writers do enjoy this much flexibility. Consider this:

I love Star Trek and Danger Mouse.
I love Star Trek, and Danger Mouse.

These are both acceptable (although GM supports the first style). You see, the author may want to make it clear that "Star Trek and Danger Mouse" is not the name of one programme.

Any grammar guide that is too proscriptive on this subject would be bombarded with examples blasting its ruling. Therefore, if I were you, I would let this ride. I judge the comma aids the reader.

If you're such a grammar pedant that you can't let it go, then I would recommend a reword:

Within the reporting product, there may be some drill-down capabilities, but they are usually not full pivot and ranking capabilities.

This turns 'but' into a coordinate conjuction and a comma is required.

Incidentally, if they are "full pivot capabilities", then "full-pivot" is correct (with a hyphen).


Here are sections on commas and conjunctions and commas in lists.

Great question

Ooops, the link was broken. It's been a long day.

Here it is again:

commas and conjunctions