Disgruntled Bankers that haven't ate speak riddles.

Subject: Disgruntled Bankers that haven't ate // Predicate: speak (verb) riddles (object).

For the Subject,

The noun is Bankers, with the addition of modifiers: Disgruntled & haven't ate.

The modifier, "haven't ate", includes a verb: have. Thus, the subject = noun + verb

The subject is a subset of Bankers, that of Bankers who are both disgruntled and haven't ate.

Clause/Simple Sentence: Bankers speak riddles

Subject: Bankers

Predicate: speak riddles

The noun of the clause is Banker, the verb is speak, and the object is riddles.

[Subject] + [Verb] + [Object]