Here's my reply in another thread. I'm also trying to get clarification on this.
Why isn't a short borrow fee considered a cost, like a commission that a broker charges to buy/sell a stock? IRS says cost basis is any cost incurred in the transaction of the the asset. The IRS would then get their money by taxing the fees that the broker made.
So wouldn't you adjust your cost basis to include the borrow fee and then include Form 8949 to show why you adjusted the cost basis of the stock?
