(Reuters) - Twitter Inc has been sweetening employee compensation packages to retain talent as the company’s user growth stalls and it stock price slides, the Wall Street Journal reported.

Four top executives left the company in January, the biggest leadership exodus since co-founder Jack Dorsey returned as chief executive last year.

The departures added to concerns about the company’s ability to make its product more engaging and generate more money from advertising.

Twitter has been offering cash bonuses to some employees, ranging from $50,000 to $200,000 as an incentive to keep them around for another six months to a year, the Journal reported on Wednesday.

The company has also granted varying amounts of restricted stock depending on when the employees started working, intending to make up for the value lost since they joined the company, the newspaper reported, citing people familiar with the matter.

Twitter’s shares have lost more than 60 percent of their value over the past 12 months.

“Competitive compensation, strong leadership and a confidence in the direction of the company are all key elements to having top talent,” a Twitter spokeswoman said in an email.

“We are investing in all three areas to ensure we maintain these employees,” she said, without providing further details.

Dorsey said in October he would give a third of his stock in the company, a stake of about 1 percent, to the employee equity pool.

Later that month, he spoke about “hiring and investing in talent” and the need for “bold rethinking.”

Twitter showed no growth in users in the fourth quarter. That was the first time that had happened since the company went public in 2013.

Twitter’s shares were unchanged at $17.66 in light premarket trading.