the amount of money there is to be made
Here between ‘money‘ and ‘there’ I guess that a relative pronoun is omitted but I’m not sure whether it is a subjective one or an objective one.
I’d appreciate any explanation.
the amount of money there is to be made
Here between ‘money‘ and ‘there’ I guess that a relative pronoun is omitted but I’m not sure whether it is a subjective one or an objective one.
I’d appreciate any explanation.
This boils down to an issue of 'that' vs 'which' as I'm sure that you weren't referring to any other relative pronoun, those aren't really relevant either way. When considering these two, we have a question of restrictive vs. nonrestrictive clauses.
First, let's establish a full sentence here so that it is easier to analyze.
The amount of money (that/which) there is to be made is astronomical.
Now, let's consider the role of 'that' and 'which' in this sentence. Using 'that' gives us a restrictive clause wherein the information referred to by the relative pronoun is essential, whereas using 'which' will give us a nonrestrictive clause wherein the piece of information that the relative pronoun refers to, while relevant, is non-essential and dispensable. Do note that 'which' should be used with a comma beforehand as a general rule of punctuation, so the sentence would be "The amount of money, which there is to be made, is astronomical" and even by looking at that you intuitively feel that this information is not really a sub-clause and surplus information but rather an essential part of the meaning that we are trying to convey.
The relative pronoun in this sentence refers to '(the money) there is to be made', which we can infer as referring to the attainability of the money by whichever party is involved. Now, the lines are a bit ambiguous when it comes to essential/non-essential information but I believe that this piece of info actually alters the meaning of the sentence significantly and can be counted as an essential clause. Therefore, I believe that using 'that' is the appropriate thing to do here (or, in context, 'that' is the omitted relative pronoun).
p.s. As seen in my discourse in the comment section with @BillJ, certain linguists do not agree with the taxonomy of 'that' as a relative pronoun, and believe that it should be classified as a subordinator instead, due to a multitude of reasons as addressed in The Cambridge Grammar of the English Language by Rodney Huddleston and Geoffrey K. Pullum in the subsections under '3.5.6. That as a subordinator (not a relative pronoun)' where it states: "Wide range of antecedent types and relativised elements, Lack of upward percolation, Finiteness, Omissibility". If you have access to the book, which can easily be accessed online, I'd recommend reading the section. This doesn't really contradict what I have written here, but it is important to be aware of different viewpoints on the topic.
the amount of money there is to be made
is a noun phrase. It can all be replaced by a pronoun:
the amount of money there is to be made would fill the largest bank vault -> It would fill the largest bank vault.
Amount is the focus of the NP.
"of money" defines "the amount" and licences the definite article.
There is an ellipsed "that" (between "money" and "there is") that introduces a relative clause "there is to be made". This relative clause modifies "the amount of money".
There is is the existential "there" such that "that there is" = "that exists".
to be made is a passive infinitive construction and can be followed by an agent, e.g. "by people".
the amount of money there is to be made = the amount of money that exists to be made by people.