She may have reasoned that it 'would have been' against her own economic self interest

She may have reasoned that it would have been against her own economic self interest to disclose the worst case scenario Source

My question is: In this sentence why are we using "would have been" instead of "would be"?

Because if I wrote the same sentence I'd write it with ".....would be...."

Kindly don't mark it as duplicate as other "would have been" vs "would be" questions don't help me figure out this sentence structure.

Solution 1:

She may have reasoned that it would have been against her own economic self interest to disclose the worst case scenario.

This sentence has an embedded content clause marked by the subordinator that:

• it would have been against her own economic self interest to disclose the worst case scenario,

This content clause has an extraposed subject. Here, dummy it occurs in the subject position and the semantic subject occurs at the end. We could rearrange it thus:

• [to disclose the worst case scenario] would have been against her own economic self interest.

To simplify it for our purposes let's paraphrase this as:

• X would have been against her interests.

This gives us a reconstituted sentence:

• She reasoned that [X would have been against her interests].

If what Hannah Lin had reasoned at the time was equivalent to:

• X will be against my interests.

... then, now that we're reporting her reasoning as a past state of affairs, we will need a past form would instead of will:

• She reasoned that [X would be against her interests]

However, if her reasoning was hypothetical at the time, the original reasoning might be better construed as:

• X would be against my interests.

Here she is thinking in an abstract hypothetical way. Notice that X in her mind is counterfactual, not real - because she is going to prevent X from occurring. It is a bit like a so-called remote conditional:

• If X happened, it would be against my interests.

Note that this is the actual thought at the time. Past tenses are used here to reflect the hypothetical and non-real way in which she is regarding the proposition. It is still a future situation that is being contemplated.

However, we are now reporting that past thought or situation as being in the past, so this is reflected by the tenses shifting backwards. So in the same way that will shifted to would in the example further above, would in this example shifts to would have:

• She reasoned that [if X had happened it would have been against her self-interests]
• She reasoned that [x would have been against her interests].

This last form is what we see in the Original Poster's example:

She may have reasoned that it would have been against her own economic self interest to disclose the worst case scenario.

This shifting back from would to would have in reported speech is quite common. However, it should be noted, that in actual fact the back-shifting of remote conditionals in reported speech is optional not mandatory. So the original Poster's preference for just would would be acceptable in either reading. However, it is nonetheless true that the original text is less ambiguous when it comes to our interpretation of the original reasoning.