If you ever use buy now, pay later at the store or when you shop online, those interest-free microloans that you mostly pay off in four installments over six weeks could soon affect your credit score.

Use of BNPL has been increasing in the last few years, and FICO now says it will unveil a new version of its credit score this fall, which would be the first to include buy now, pay later.

But at least two of the big companies that offer these loans, Klarna and Afterpay, say they won’t share their data with the credit bureaus until they know it won’t harm their customers.

You can use buy now, pay later for almost anything — a couch, new clothes, groceries. Just walk into a store or go online, pick what you want, and check out — no credit card and no money down.

“These are very short-term loans, they’re usually paid off very quickly,” said Chi Chi Wu, staff attorney at the National Consumer Law Center.

People often take out a bunch of BNPL loans for a bunch of small purchases, she said — which is one reason it’s tricky for credit bureaus to factor them into your credit score, at least with their current models.

“Traditionally, credit scoring models have assumed if you’re opening up a whole bunch of new accounts all at once, that’s a sign of financial trouble,” Wu said.

So, if it’s considered a new line of credit every time you use buy now, pay later, Wu said that could hurt your score.

That is not the approach they would use, per Liz Pagel, senior vice president and consumer lending leader at TransUnion, adding that the credit bureau is working to come up with an entirely new model instead to more accurately evaluate BNPL loans.

“We believe this could be one of the most meaningful financial inclusion opportunities in a generation,” she said, because most customers who use buy now, pay later pay on time, which could help their credit scores.

But Chi Chi Wu at the National Consumer Law Center said it’s not just what the credit bureaus will do with the data.

“We don't know how lenders are going to view this,” she said. “Are they gonna look positively upon BNPL loans that are repaid, or whether they'll draw negative inferences and assume that the person might be having some sort of financial trouble” — just because they used buy now, pay later in the first place.