Online broker Ameritrade (AMTD, news, chart) saw bearish order flow Tuesday. The stock rose 41 cents to $20.84 and set a new 52-week high of $21.42 midday. Yet, despite the stock’s strength, sentiment in the options market was less than cheerful. 6,670 AMTD puts and 1,025 calls traded on the day. The September 20 puts, which come off the board in 17 days, were the most actives. 5,100 contracts traded, with 97 percent of the day’s volume trading offerside. October puts with strike prices ranging from 17.5 to 22.5 also saw an increase in buying interest. There was no news on Ameritrade to explain the jump in put buying. However, the company did announce that it would present at the Lehman Brothers Financial Services Conference on September 9 and also at the Scotia Capital Financial Summit Conference on September 10.