The 1910s and 1920s brought several years of severe storm losses, causing the need for more assessments, which went up from 10 cents to 20 cents per $100 insured. Storm losses in 1912-1913 were so severe that the Windstorm Company was obliged to borrow money to pay them. One storm in 1913 kept 15 field adjusters busy for six weeks. High school girls were hired part-time to keep up with the paperwork, and this clerical department eventually began calling themselves "the Windstorm Girls".
Storms in the early 1920s created over a half million dollars in losses. One in every 13 policyholders suffered a loss. Again, money was borrowed to pay the losses and more clerks and adjusters were hired so the company could maintain its reputation for prompt payment.
As these storms moved through the area, the company underwent some shifting in its management. In 1912, four of the original board members died and were replaced by younger men. D.W. Rogers remained secretary until he lost his bid for re-election in 1918, after 33 years of service. The first full-time president, Mr. L.W. Sunday, was elected in 1924, and the board elected with him endured for 14 years.
Still, the company grew and in 1920 its name was changed to Michigan Mutual Windstorm Insurance Company. In 1923, the board purchased a lot for a new office building at State Street and Broadway and contracted for a fireproof office building. They moved into the new office in 1924, and in 1925, because the company generated so much postal business, a new post office was built across the street. By 1925, the Windstorm Company was the second largest mutual windstorm company in the world with 90,000 members sharing $300 million in coverage.