Which agency, and therefore which lender sees it. Furnishing is voluntary and per agency, so a rent reporting arrangement reaches whichever nationwide agencies that particular service has a relationship with, and that is often one or two rather than three. A borrower has several credit files at once, and a lender pulls the one it pulls. So the practical value of a rental tradeline depends on a matching that the tenant does not control: the agency the service reports to has to be the agency the lender reads.
Whether it moves a score is a model question, not a data question. Getting a tradeline onto a file is one thing; a model choosing to weight it is another. Fair Isaac states the position for one named version: in FICO Score 9, "Rental history, when it's reported, factors into the score. This may be especially beneficial for people with a limited credit history." That is a claim about version 9. Fair Isaac separately states that each lender decides for itself which version to order, and that for mortgages lenders typically use FICO Score 5, FICO Score 4 and FICO Score 2 depending on the bureau, all of which predate version 9. Nothing here should be read as a claim about how any other version treats rental data; that is not published, and the honest formulation is to name the version whenever the point is made.
The asymmetry that the marketing does not mention. Rent reporting is usually presented as a way to record good behavior. But a furnisher that is reporting an account has an accuracy obligation covering the whole of it: Regulation V defines accuracy, at 12 CFR 1022.41(a)(2), as information that "Reflects the consumer's performance and other conduct with respect to the account or other relationship," and the interagency guidelines direct furnishers to update information "to reflect the current status of the consumer's account." So where a service is furnishing a rental tradeline, a month paid late is part of that account's performance. Some services report only positive data by design, and some report the full history, and which applies is a term of the particular arrangement rather than something that can be assumed. That term is the one worth reading before enrolling, and it is usually not the one the marketing leads with.
Negative rental information reaches consumer reports through a completely different door, and it always has. The Bureau's own description of Experian RentBureau notes that it collects from "collection companies" alongside property managers, and unpaid rent that goes to collection is an ordinary collection account. Eviction filings are public records and reach tenant-screening files independently of anything the tenant opts into. So the choice is not between a rental history that reports and one that does not; it is between a file that records rent when it goes wrong and one that records it in both directions. The rent and eviction pages carry the underlying mechanics.
How much of the renter population is covered is not a published number, and this page will not supply one. The Bureau bought rental payment data for its own research from one nationwide credit reporting company, and describes the supply side plainly: "Property management companies can choose to furnish data to the credit reporting company via their property management software provider." It also cautions that because furnishing is a choice, "the data are not necessarily representative of renters in the U.S. overall," and that the renters who do appear come from higher-income, more urban and more populous census tracts than U.S. renting households generally. Two things follow. The coverage is uneven in a way that correlates with income, which is the opposite of what a policy aimed at thin files would want. And a percentage of renters covered is not a figure any source states, so any such figure quoted elsewhere should be traced before it is repeated.
One entitlement worth knowing. A specialty agency holding rental data is a consumer reporting company, and the CFPB's listing states that Experian RentBureau "will provide one free report every 12 months if you request it." A tenant who has been denied a rental can therefore read the file that was used to decide, which is a right that exists whether or not they ever opted into reporting anything.