The research looked at companies that offered both an ESPP and a 401(k) and companies that offered only the latter. The ESPP "effect" could be seen in all companies, regardless of size. However, it had the most impact on smaller companies of fewer than 500 employees, where only 9 percent of workers took out new 401(k) loans when an ESPP was also available — compared to 14 percent for employers that only offered a 401(k). 

Small companies also had a significantly lower outstanding loan rate. Only 14 percent of ESPP/401(k) workers had an outstanding 401(k) loan balance, compared with 23 percent of employees at 401(k)-only companies. 

At large companies — those with more than 10,000 employees — that had both an ESPP and a 401(k), employees borrowed an average of $2,000 less than employees at firms with only a 401(k). In addition, those employees at firms with both plans had an average outstanding loan balance that was $3,000 less than employees whose firms did not offer ESPPs. 

Fidelity said that ESPPs, often offered to employees as a complementary workplace savings vehicle to their 401(k), are increasingly important among workers evaluating a new job opportunity. 

According to a recent Fidelity survey, 86 percent of respondents under 40 years old said they would want their new employer to offer a company stock plan if they changed jobs; 40 percent of overall respondents in that survey consider a company stock plan as a "must have" benefit when making a decision to change employers. 

"Savings in an employee stock purchase plan can present a viable option for workers who need to draw on their savings for financial purposes. Company stock, which is often purchased at a discount and is kept in an account outside of an employee's 401(k) account, can be cashed in without the risks and tax implications sometimes associated with tapping a 401(k) account and the money does not have to be repaid if an employee changes jobs," Kevin Barry, executive VP, stock plan services at Fidelity Investments, said in a statement.