All of these reactionary “fixes” won’t actually fix anything and will prevent the market from accurate price discovery in the short term which will mean worse outcomes in the long term. You are in good company with the big-idea folks running our central government like they’re playing god with tinker toys. They overestimate their abilities and underestimate their stupidity and inability to y’know TELL THE FUTURE.

Short-selling is vital especially during market declines, because it means a bid is incoming. That’s a lifeline to people who actually need to sell. It increases bid volume when the most exposed market participants need it most. Absent that bid, who knows what other asset will see an even bigger decline. Treasurys? Real estate? Your business’s contract?

HFT is market liquidity. You might not like it, but if you take away over half of the market’s liquidity, what do you think will happen during a bear market? Will bigger ask-spreads be helpful?

A “small tax” only makes ownership more expensive, which facilitates more urgent selling at the margins.

Taxing oil up to $50 a barrel would be ruining the one tiny silver lining of this decline. Who do you think pays these taxes? Who do you think benefits from low oil prices? The answer is: the consumer. Which consumers are most injured by your tax scheme? The poorest! Whyyyyyyyyy would you do this!?