GMAT Sentence Correction (SC) | Re: Not one of the potential investors is expected to make an

Not one of the potential investorsis expected to make an offer to buy First Interstate Bank until a mergeragreement is signedthat includes a provision for penalties if the deal were not to be concluded.

If you go by meaning then absolutely 'that' refers to 'merger agreement'.

Even if you don't want to go by meaning but by structure.

Then yes the noun modifier can jump to modify far away noun if the critical predicate falls between.

Critical predicate=is signed
Subject=agreement
Modifier=that...

Hope
...

---