By Svea Herbst-BaylissNEW YORK (Reuters) -Irenic Capital Management built a sizable stake in Workiva, arguing the financial reporting software maker needs to improve its operating efficiency, refresh its board and consider a potential sale. Irenic is pushing for Workiva to review strategic alternatives with fresh board oversight, capitalizing on strong private equity appetite for financial software companies, said the sources who were not allowed to discuss the private talks publicly. A representative for the company was not immediately available for comment while an Irenic representative declined to comment. IRENIC TARGETS WORKIVA AFTER STOCK DECLINEIrenic ranks among the top 10 investors in Workiva and its push for changes is becoming public less than three weeks after the company held its investor day. Irenic has been frustrated with the company's financial performance with the company trading at a 27% discount to application software rivals like Workday and ServiceNow, the documents show.