What? "Doesn't seem to be an accurate statement"? What part? Those numbers are actually conservative. According to Yahoo Finance[0], it's actually 93% of the stock market is owned by the wealthiest 10% of American households. And the bottom 50% of Americans own ~1%. You "seem" to be mistaken and you're talking out of your ass.
>>nish__+(OP)
The article you're citing doesn't link to its sources, but seems to be talking about direct stock ownership by households, and not explicitly stating how it's accounting for investment funds.