 TD Ameritrade Holding Corp. NASDAQ: AMTD clients participated in the electric vehicle craze last month.According to the Investor Movement Index, an index that measures a sampling of client accounts with at least one trade in the past month, TD Ameritrade clients were net buyers of electric vehicle stocks like Tesla Inc NASDAQ: TSLA, Nio Inc NYSE: NIO, and Nikola Corporation NASDAQ: NKLA in July. Overall trading volume in all three stocks increased last month with mixed performance--shares of Tesla and Nio rallied to new all-time highs, while Nikola continued its fall from June.TD Ameritrade clients were also net buyers of Dow components Pfizer Inc. NYSE: PFE, Apple Inc. NASDAQ: AAPL, and Microsoft Corporation NASDAQ: MSFT during the month, as well as names like Crowdstrike Holdings Inc NASDAQ: CRWD and American Airlines Group Inc NASDAQ: AAL.Some of the stocks that were net sold during the period include Roku Inc NASDAQ: ROKU, Facebook, Inc. NASDAQ: FB, Costco Wholesale Corporation NASDAQ: COST, FedEx Corporation NYSE: FDX, Twitter Inc NYSE: TWTR, and United Airlines Holdings, Inc. NASDAQ: UALTD Ameritrade Chief Market Strategist JJ Kinahan said stocks cited by the firm as being net bought or net sold arent necessarily the ones with the greatest buy or sell imbalance among clients, but that experienced the greatest month-over-month changes in trading activity.Increased Exposure To Stocks Overall, the Investor Movement Index increased to 4.63 in July, a 1.76 increase from June. This marks the third straight month of gains for the index after it fell to an all-time low of 3.9 in April. The trend suggests that TD Ameritrade clients have been steadily increasing their market exposure over the past three months. Source: TD AmeritradeWhat the IMX tells me is people have a lot of doubts still because there are still so many headwinds right now, said Kinahan. There are so many unknowns that people are nervous to be all in.As far as the types of stocks clients are net buying, Kinahan observed a dichotomy in what appears to be capturing client attention.Its a little bifurcated between stocks youre going to have as an investment like Pfizer, and then on the other side the Nikolas and Crowdstrikes which are more speculative.Kinahan also observed that clients dont appear to have a clear conviction on social media stocks one way or the other.What I find interesting is the social media space is one where people cant decide what to do. They were buyers of Facebook and Twitter a couple of months ago, and now its at a point where people are wondering Do I really want to be involved there? Once congress has you in their sights, anything can happen.See more from Benzinga FANG Stocks Continue To Rise The Growing Email Scam Thats Almost Impossible To Reverse Gold Just Hit An All-Time Nominal HighHow To Play The Trade With ETFsC 2020 Benzinga.com. Benzinga does not provide investment advice. All rights reserved. 