I personally will collect the bets on which firm will be the first to argue that, because it only reports semi-annually, its stock price cannot be presumed to be efficient and therefore it cannot be the target of a fraud on the market Section 10(b) class action.

Headline quote from the SEC proposal:

The proposed amendments, however, could also lead to efficiency reductions. As discussed above, a switch to semiannual (or hybrid) reporting would likely increase information asymmetries, thereby reducing the informational efficiency of share prices and reducing stock market liquidity for the companies that move away from quarterly reporting.

Also worth noting, to determine if a market is efficient, courts look to whether the company qualifies for S-3 filing – but the SEC proposes to make that a lot easier, too.