Things continue to go well for TD Ameritrade (NASDAQ:AMTD). The popular discount brokerage announced that it would post March-quarter results exceeding its earlier guidance of $0.28 in profits per share.

Trading has gone well for the discount-brokerage industry. Earlier this month, Charles Schwab (NASDAQ:SCHW) announced that February was its best single month for new assets since January 2001. Even though brokers like Schwab and E*Trade (NYSE:ET) saw a sequential dip in trading for the month of February, it followed an outstanding January.

Thanks to an uptick in trading activity, the leading players have been trimming away at some of the small account maintenance fees that were instituted when trading commissions started to dry up a few years ago.

It's the perfect storm for companies like TD Ameritrade. Individual investors are buying back into the market, and for those with leveraged accounts, every Fed uptick is opening the door for higher-margin rates as banks adjust their prime lending rates. The financial results over the past few quarters have been highly encouraging.

That's why our discount broker comparison table may be a good place to see what the leading online brokerage firms are charging these days. It's important not to be too greedy now that the going is good, so it's comforting to see the top dogs implementing customer-friendly policies.

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Longtime Fool contributor Rick Munarriz won't be making an unsolicited offer to buy any discount brokerage outright, though he may consider buying shares in some of the players in the future. He does not presently own shares in any of the companies mentioned in this story.The Fool has a disclosure policy. Rick is also part of theRule Breakersnewsletter research team, seeking out tomorrow's ultimate growth stocks a day early.