American private equity firms Hellman & Friedman LLC and JMI Equity are said to be exploring a sale of human resources management software firm Kronos Inc. Kronos could be valued at more than $4 billion. 

Sources told Reuters on Wednesday that Kronos is in early-stage talks with a small group of private equity firms about a potential deal. The group includes KKR & Co. LP, TPG Capital LP and Bain Capital LLC. American computer technology corporation Oracle Corp. and German software firm SAP AG would be natural buyers for Kronos. But the two companies have so far shown little interest, the report said. 

Hellman & Friedman is said to be working with Morgan Stanley on the sale of Kronos. The software company has an annual earnings before interest, tax, depreciation and amortization (EBITDA) of around $350 million, Reuters said.

Kronos provides workforce management solutions to companies and organizations in more than 100 countries. Hellman & Friedman, along will smaller private equity firm JMI Equity, took Kronos private for $1.8 billion in 2007, the report said.