Today’s tickers: AMTD, XRT, BTU & NG AMTD  - TD Ameritrade Holding Corp. –  Put options on TD Ameritrade are popular on the final trading session of the week, with shares in the financial services company trading 0.85% lower on the day at $18.76. Investors may be scooping up puts on the largest U.S. online trading firm following comments from the company’s chief executive regarding concerns that the slower pace of client trading activity in the context of a more uncertain economic climate may endure through the summer months. In-the-money put options in the August contract, which expire after TD Ameritrade reports third-quarter earnings on July 19, are drawing the most trading traffic today. It looks like investors purchased around 2,175 puts at the August $21 strike for an average premium of $2.77 each. Bears traded more than 3,400 puts at the lower August $20 strike on previously existing open interest of just 381 contracts. Roughly 3,000 of the lower-strike puts were picked up for an average premium of $1.82 a-pop. Investors long the August $20 strike puts make money in the event that AMTD’s shares fall another 3.1% to breach the average breakeven point on the downside at $18.18 by expiration day in August. Greater demand for TD Ameritrade put options helped raise the stock’s overall reading of options implied volatility 12.4% to 31.77% as of 1:00pm in New York. XRT  - SPDR S&P Retail ETF –  A large ratio put spread initiated on the retail ETF suggests one big options strategist is positioning for substantial, albeit limited, bearish movement in the price of the underlying fund through July expiration. Shares in the XRT, an exchange-traded fund designed to mimic the performance of the S&P Retail Select Industry Index, dropped 2.4% to an intraday low of $49.15 today. The trader…