[1] An item of evidence is said to be material if it has some logical connection to a fact of consequence to the outcome of a case.
Materiality, along with probative value, is one of two characteristics that make a given item of evidence relevant.
Which issues must be factually proven are therefore a product of the underlying substantive law.
[3] Within the context of corporate and securities law in the United States, a fact is defined as material if there is a substantial likelihood that a reasonable shareholder would consider it important in deciding how to vote their shares or invest their money.
Materiality is particularly important in the context of securities law, because under the Securities Exchange Act of 1934, a company can be held civilly or criminally liable for false, misleading, or omitted statements of fact in proxy statements and other documents, if the fact in question is found by the court to have been material pursuant to Rule 10b-5.