By 1969, during production of the HRO-500, National Company went bankrupt. Redundancies followed and the main plant in Malden, Massachustts was closed and torn down. Remaining production continued at the smaller Melrose, Massachusetts plant.

In the early 1970’s National Company Inc was acquired by an investment company - Louis C. Learner. Learners made sweeping managerial changes in an attempt to revive its fortunes.

The new management set up a second company called National Radio Company Inc. which handled all commercial sector work whereas government contracts continued to be charged to National Company Inc.

But the National Radio Company itself was declared bankrupt in 1974 and its name and assets sold to its principle creditor who in turn sold them to FAN-WEL Corporation.

The National Company continued as a government contractor through the 1970’s and 80’s but never achieing its former success. It finally ceased business in 1991.