Pacific Investment Management Co. used to rely heavily on one man to make many of its key investment decisions. Now it’s betting a big part of its future on millions of lines of software code.

Pimco will open a new office in Austin, Texas, later this year to help recruit more tech-savvy workers who might otherwise spurn the bond manager for traditional software companies, people familiar with the matter said. The Newport Beach, Calif.-based firm plans to grow its workforce by 10% this year, adding about 250 new staff.

Many...