Interesting that out of five corporations, only two letters are represented. Ok, "A" is ranked third in frequency in the English language, but the other one I avoided in these sentences? Not even in the top twelve.
Freqency at the begining of words is likely to be different to frequency anywhere in the word. Regardless, "a" has the highest frequency in the company names, when spelled out in full (occurring 6 times, in 3 of the 5 corporations)