Though August's financial markets were extrememly subdued, that quiet is not expeted to last past Labor Day. Money managers and investors are returning from vacations this week and preparing to get back to the grind for September, which is known to be an uncomfortable month for bulls.

Below are this month's financial events you should know about:

1. Sept. 4-5 G-20 summit: The 20 most powerful economies, known as the G-20, hosted its summit this past weekend, during which economic leaders pledged to revive global trade and investment—though experts say the commitment lacks concrete steps and fear China won't lead by example.

2. Sept. 8 European Central Bank policy meeting: Experts expect ECB president Mario Draghi to continue worrying about the scarce supply of government bonds available for the ECB to buy and is likely to announce a six-month extension to the bank’s asset-buying program until September 2017, according to London economist Anatoli Annenkov, MarketWatch reports.

3. Sept. 20-21 Fed, Bank of Japan policy meetings: Since the odds are in favor of the Fed staying the course at its upcoming meeting, the real fireworks will likely come from the BoJ, where the country may re-evaluate its fiscal policy and the use of negative rates. [MW]