A new generation of lenders is challenging the usefulness of one of the bedrocks of the modern financial system: the FICO score.

A San Francisco company that offers student-loan refinancing, mortgages for high-priced homes and personal loans, has decided to do away with FICO scores in its credit decisions, making it one of the highest-profile lenders to do so.

A variety of smaller Silicon Valley-backed companies also have looked to move beyond the traditional FICO credit score, calculated since the late 1980s by Fair Isaac Corp. Some of the most significant include Affirm Inc., which finances the purchase of consumer goods at the point of sale; subprime lender Avant Inc.; and Earnest Inc., which makes student and personal loans.

In moving away from FICO, most of these online lenders are betting that their new scoring models aimed at expanding credit will hold up in a tougher business environment.

One of the largest private online lenders with an estimated value of about $billion, SoFi has arranged more than $6 billion in loans since its 2011 founding, and now believes it has enough data to decide on the creditworthiness of applicants without looking at their FICO scores.

A staple of consumer lending for more than two decades, FICO scores are used in 90% of all credit decisions, according to research firm CEB TowerGroup.

Fair Isaac had been assessing creditworthiness decades before it created the FICO score.