Technology-focused private equity firm Thoma Bravo is planning to seek about $10 billion for its 13th buyout fund, according to people with knowledge of the matter. Thoma Bravo has held preliminary talks with backers about a return to the fundraising market this year, said the people, who asked not to be identified because the details are private. If the firm collects $10 billion, the fund would be more than 30 percent larger than its predecessor pool, which closed on $7.6 billion in 2016. Discussions are early and the fund’s target may change, the people said.