Here's the trademark information about Tenma:

http://electronics.zibb.com/trademark/tenma/29495179

Tenma trademark owners:

Premier Farnell Corp.
7061 E.Pleasant Valley Road
Independence, Oh 44131 US


Premier Industrial Corporation
4500 Euclid Avenue
Cleveland, Oh 44103 US

Turns out Premier Farnell owns MCM Electronics:

http://en.wikipedia.org/wiki/Premier_Farnell