The phrase "a material interest" is correct and usable in written English.
It is typically used in legal or financial contexts to refer to a significant or substantial interest in a matter or transaction.
Example: "The board must disclose any potential conflicts of interest, especially if they have a material interest in the outcome of the decision."
Alternatives: "a significant interest" or "a substantial interest".
Thus they have a material interest in retaining them.
There can be no occasion, and indeed our time and space forbid that we should at present enumerate these: they will be sufficiently in the recollection of those of our readers who feel a material interest in political affairs.
Because all the forces with a material interest in its perpetuation are paying attention.
Such is the inherent defect of law-enforcement unionism: It's peopled by those with a material interest in maintaining and enlarging the state's most indefensible practices.
Finally, because we live in this system full of mistrust, we are required to do awkward things like vouch for our own trustworthiness, so before I sign off, let me note: Research standards require me to disclose that I have a material interest (i.e., winning) in reaching my conclusion that underhand serving is ethical, since I stand to gain from it, performance-wise.
So far, the entire negotiating process has been about as secret as it gets—unless you're involved in a business that has a large material interest in what's going on.
This was because the Big Apple Circus, conceived when the two men were itinerant jugglers who drove cabs and picked grapes, was born of something almost antithetical to material interest, a raw creative anarchy coupled with a desire to provide children, whether they were from Park Avenue or the South Bronx, a shared sense of cultural experience.
At this time, the Partnership is not aware of any transactions, since the beginning of the Partnership's last fiscal year, or any currently proposed transactions, in which the Partnership was or is to be a participant involving amounts exceeding $120,000, and in which Mr. Perry had or will have a direct or indirect material interest.
But from an ethical point of view we have to show that if we found anything that was of material interest to a patient that we had to have a system in place to provide service for that patient.
Boron phosphide (BP) is a material of interest for development of a high-efficiency solid-state thermal neutron detector.
The company Mooney works for does not mine or export coal, which therefore does not amount "to a material personal interest", the report said.
