RPX Corp. on Tuesday announced a deal to be acquired by private equity firm HGGC for $555 million, the latest in a series of shake-ups at the San Francisco-based defensive patent aggregator in recent years.

The move follows RPX’s disclosure in February that it was reviewing a full range of strategic alternatives amid flat revenue and massive impairment losses in the fourth quarter of 2017. According to the announcement, Palo Alto-headquartered HGGC would initiate the all-cash tender offer for RPX’s stock at $10.50 per share.