Well, one percent tax would eliminate very huge fraction of needless back and forth speculative trading, while doing nothing to hurt Google.
I think you need to justify the "needless" in your description of such back-and-forth speculative trading, as it a) has gone unquestioned b) is not self-evident, and c) otherwise begs the question about whether we need to actually do anything about it at all.
The last point reminded me of speculation from the recent LessWrong article Conspiracy Theories as Agency Fictions:
Before thinking about these points and debating them I strongly recommend you read the full article.