Challenging Times
The Beta Beta chapter of Theta Upsilon Omega at Miami University couldn't survive the height of the Great Depression. National unemployment was 24.9% the year the chapter had its charter suspended. Miami itself weathered this time, experiencing little change and not losing enrollment as was common place among universities. Only about 10 percent of of Miami students in the 1930's were on government subsidies. Enrollment was still comparatively low and had approximately 2,000 enrolled students, men and women.
For Theta Upsilon Omega nationally, growth 
stalled during the Great Depression and in 1938 the fraternity merged into Sigma Phi Epsilon. Four chapters merged with existing chapters, while seven eventually rechartered as such.
The Great Depression lasted from 1929 until December 1941 when the USA was drawn into WWII. What was a challenging economic environment quickly turned into recovery as mobilization for war finally lifted the American economy. It was still a challenging time for fraternities as men went off to fight in the war instead of going to college. The civilian enrollment at Miami dropped to just over 800, but military enrollment grew after the establishment of a naval radio training school.
Golden Age - SigEp Plans Growth
In 1944, the G.I. Bill was established giving many men returning from war the opportunity to go to college, making the bill one of the landmark pieces in American history. As a result of it, more than two million service men and women would go to college after the war, and Miami was one of the principal beneficiaries. WWII ended in later 1945 and Miami's enrollment would subsequently jump from 2,200 to 4,100 students. Miami needed to construct temporary housing upon the student influx. 'Vet Village' on south campus (where the Recreational Center is today) was one of these transformed areas as well as 'Miami Lodges' (where Porter, Dodds, Stanton, and Anderson Halls now are) which housed the military influx; and of course, fraternity houses provided additional space for the overflow and began to thrive again.
For Sigma Phi Epsilon, Executive Director Bill Hindman and Frank Ruck had the foresight to see this opportunity and position the fraternity to grow. They determined that even smaller state and private schools would be able to support Greek systems and went school to school establishing chapters. As these colleges grew, SigEp catapulted to the top of the fraternity world.
This period paved the way for what's considered the 'Golden Age of Fraternities' and also set the course in 1948 for the Beta Beta chapter of Theta Upsilon Omega (now Sigma Phi Epsilon) to be reestablished at Miami. This new group organizing itself as 'The Hathor Club,' would soon petition for a charter and evolve into the OH Eta chapter of Sigma Phi Epsilon.