Agency History

The agency known as Guaranty Insurance Services was founded in 1957 in Texas under the name Timber Line Company and was part of the Temple-Inland family. The expansion of the Texas agency began in 1992 through 1999 by acquisition of six agencies in strategic locations including Arlington, Austin, Baytown, Houston and San Antonio followed by the acquisition of Dallas-based TCT Insurance Agency in 2004.

The following year, Guaranty increased its holdings by acquiring a strong multi-location agency in Southern California, Walter Mortensen Insurance Agency. The respect and strong name recognition of WMI in Bakersfield and the surrounding communities have allowed them to operate in these areas since 1919.

Guaranty’s Texas footprint continued to increase in 2007 with the purchase of a Tyler/Henderson agency, Hilliard Box Insurance. A strong presence in East Texas since 1985, HBI continues to serve those communities today.

In April 2011, Guaranty became part of INSURICA Insurance Management Network and rebranded in 2012. Our clients now have access to many new resources available through the vast INSURICA network delivered by the same local relationships they’ve come to trust.

Areas of Specialization

Areas of specialization for this office include: technology, healthcare, construction, landscaping and residential property management.

What Makes Us Unique

We are proud to now offer the full resources of INSURICA to serve the needs of Dallas, Plano and the metroplex.


Our producers are proud of their long-term commitment to civic leadership in the Dallas community.