July 21 (Reuters) - Tax software company Avalara, which

went private in 2022, disclosed on Monday it had confidentially

filed for a U.S. initial public offering, indicating plans to go

public again amid growing investor optimism for IPOs.

The terms of the offering were not disclosed.

U.S. IPO activity, sluggish at the start of the year, is

gaining momentum following robust investor demand for new

offerings.

Avalara went public in June 2018 but was taken private in

2022, when it was acquired by private equity firm Vista Equity

Partners in a deal that valued the company at $8.4 billion,

including debt.

The filing underscores the broadening of the U.S. IPO market

- from originally venture capital-backed deals focused on growth

to private equity-backed offerings where the IPO acts as a

catalyst for capital structure changes, said IPOX CEO Josef

Schuster.

In April, tax firm Andersen had also filed confidentially

for a U.S. listing.

Founded in 2004, Avalara runs a cloud-based software

platform that helps companies with tax compliance. The

Seattle-based company counts Adidas, Crocs ( CROX ) and Reebok

among its customers.

Companies often file for IPOs confidentially to keep details

about their financial and strategic plans private, while

engaging with regulators and potential investors.