The S&P 500 dropped over 1.5% on Wednesday. Investors, meanwhile, focused on some notable insider trades.

When insiders sell shares, it indicates their concern in the company's prospects or that they view the stock as being overpriced. Either way, this signals an opportunity to go short on the stock. Insider sales should not be taken as the only indicator for making an investment or trading decision. At best, it can lend conviction to a selling decision.

Below is a look at a few recent notable insider sales. For more, check out Benzinga's insider transactions platform.

Halliburton

• The Trade: Halliburton Company (NYSE:HAL) EVP, Secretary and CLO Van Beckwith sold a total of 4,295 shares at an average price of $42.60. The insider received around $182.97 thousand from selling those shares.
• What's Happening: Wolfe Research recently upgraded the stock from Underperform to Outperform and announced a $51 price target.
• What Halliburton Does: Halliburton is one of the three largest oilfield service firms in the world, offering superior expertise in a number of business lines, including completion fluids, wireline services, cementing, and countless others.

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Interactive Brokers Group

• The Trade: Interactive Brokers Group, Inc. (NASDAQ:IBKR) Chairman Thomas Peterffy sold a total of 40,000 shares at an average price of $76.51. The insider received around $3.06 million as a result of the transaction.
• What's Happening: Interactive Brokers Group posted upbeat Q4 results.
• What Interactive Brokers Does: Interactive Brokers Group Inc, or IB, conducts broker-dealer agency business and proprietary trading business worldwide.

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Roblox

• The Trade: Roblox Corporation (NASDAQ:RBLX) Chief Business Officer Craig Donato sold a total of 2,000 shares at an average price of $37.48. The insider received around $74.96 thousand from selling those shares.
• What's Happening: Roblox recently said its daily active users in December jumped 18% year-over-year to 61.5 million. Hours engaged climbed to 4.7 billion last month, up 21% year-over-year.
• What Roblox Does: Roblox operates an online video game platform that lets young gamers create, develop, and monetize games (or "experiences") for other players.

Ciena

• The Trade: Ciena Corporation (NYSE:CIEN) Sr. VP, General Counsel David M Rothenstein sold a total of 3,500 shares at an average price of $50.89. The insider received around $178.12 thousand from selling those shares.
• What's Happening: Ciena, last month, reported better-than-expected Q4 sales results.
• What Ciena Does: Ciena Corp is a network strategy and technology company. It provides network hardware, software, and services that support the transport, switching, aggregation, service delivery, and management of video, data, and voice traffic on communications networks.