I know that brokers must buy the stock if you purchase the stock under your retirement account. how do i know the broker has actually purchased the stock and isn't holding my cash and only has IOU. Do brokers/market makers obligated to buy stock even though the stock says it's not shortable. recently, SEC still allows market makers to short for business reasons or providing liquidity to the market. even though some stocks cannot be shorted by retail, market makers still have the privillege of shortin the stock naked. i think the market makers lobbied the SEC on this rule and is absolutely bogus just like madoff pioneered trading agains client using algorithms and computers.