Recent data from the FRX‐C [Proceedingsofthe7thSymposiumonthePhysicsandTechnologyofCompactToroids(Los Alamos National Laboratory, Los Alamos, NM, 1986), p.142] and FRX‐C/LSM [Proceedingsofthe14thEuropeanConferenceonControlledFusionandPlasmaPhysics(European Physical Society, Madrid, 1987), p. 485] field‐reversed theta pinches are presented concerning heating, internal flux, and particle retention after formation. These results extend the data base of field‐reversed configuration plasmas to larger dimensions. Good agreement is found for collisionless plasmas with some existing formation laws [Fusion Technol.9, 48 (1986)] and the main result is confirmation of improved internal flux retention for plasmas of larger radius. Some simple semiempirical laws are proposed, which allow a global analytical formation model. This model should provide reasonable estimates of the equilibrium parameters of field‐reversed configurations formed in theta pinches.