Quote from DaveN:
Ahhh, tax law. I don't know enough to explain it, but I can speculate. I am neither an attorney nor CPA; I have no special insights or experience. The following is my opinion only:
It seems to me that over the years, equities have been used as and considered to be the "investments" made by the retail public. Lawmakers and policymakers have seen the need to protect and regulate investors to eliminate fraud and deception, both against the government and against the investor. So you have an individual section, Schedule D, of the tax return which specifically treats this area.
Since some of those protective laws address individual transactions, e.g. wash sales, and basis calculations, each transaction needs to be listed and is available for scrutiny. Generally, investors don't trade often, especially before electronic trading, so listing trades on a tax return wasn't especially onerous. Over the last decade, with the explosion of electronic trading, I cannot imagine what lengths of entries the IRS and tax professionals are seeing on Schedule D's.
As you know, futures are short term contracts which expire, so by definition, they aren't likely an investment vehicle. So they get their own section of the tax code, 1256, which takes more of a business approach (lump sum reporting recognizes the short term nature of these vehicles).
A similar argument can be applied to spot currency. Transactions are likely not an investment, but rather an exchange for a business purpose or speculation.
Of course, there's always Mark-to-Market and Trader Status which you can consider for your equities trading.