This is an important point, assurances by brokerages that your shares are safe and available to you are only good when the market is normal. In a price squeeze, as Riz points out, they may not be able to locate them because the sellers can't get out right away to close their position.

Plus when when brokerages lend them out the purpose is to allow the market manipulators to push the price down, which cuts off that avenue of funding (without heavily diluting current shareholders).

Think about that. It is wrong to deny funding to a company that is creating life-saving molecules (not potato chips) to treat people for diseases. If they could protect banks during the financial meltdown in 2008, they can protect preclinical companies. Let's hope for some reform there with new SEC. We'll see.

My shares are all in cash accounts or IRAs which are equivalent to cash accounts and can't be borrowed from.

Keep on keeping on