General Motors CEO Mary Barra and Salesforce CEO Marc Benioff both sold millions of dollars worth of their own stock in the waning days of May, according to securities filings and information compiled by VerityData. Barra sold more than $27 million worth of stock on May 28, joining several other GM insiders who have done similar trades this year. Meanwhile, Benioff sold more than $12 million worth of shares over the course of several days. Both execs made the sale as part of 10b5-1 trading plans. Those plans are filed with regulators ahead of time to set out when an executive will trade shares in the coming months and years. Benioff’s sales in this data summary from Verity took place on May 24, 28 and 29. The Salesforce CEO had been selling stock consistently over recent periods, and subsequent filings showed that he made another sale on May 30. Salesforce’s released its first-quarter report after the market closed on May 29. The stock fell more than 19% the following day. Insider buying and selling is tracked closely by many professional fund managers. The idea is that these trades could possibly be a signal about what an exec or board member thinks of the direction of the company or the valuation of the stock. Here are the biggest insider sales in the final days in May, according to VerityData and securities filings: General Motors CEO Barra sold 626,300 shares at an average price of $43.46 for a total of $27.22 million. Trades made pursuant to a 10b5-1 trading plan. Salesforce CEO Benioff sold 45,000 shares at an average price of $270.70 for a total of $12.18 million. Trades made pursuant to a 10b5-1 trading plan enacted 12/29/23. Squarespace CEO Anthony Casalena sold 135,100 shares at an average price of $43.50 for a total of $5.88 million. Trades made pursuant to a 10b5-1 trading plan enacted 8/11/23. Applied Materials CFO Brice Hill sold 20,000 shares at an average price of $222.34 for a total of $4.45 million. Texas Roadhouse CEO Gerald Morgan sold 15,000 shares at an average price of $171.70 for a total of $2.58 million. Trades made pursuant to a 10b5-1 trading plan enacted 2/27/24 and reduced holdings by 16%. There was notable insider buying in the final days of May as well, though from lower profile executives. The biggest move came from two insiders at a small investment firm — Oxford Lane Capital — who combined to buy $50 million worth of the stock. That is a sizeable position for a company with a market cap below $2 billion. Elsewhere, the $2.4 million buy from Petco director Cameron Breitner is worth highlighting because Breitner is a senior advisors with CVC Capital Partners, one of the company’s biggest shareholders. Here are the biggest insider buys, according to securities filings and VerityData. Oxford Lane Capital CEO Jonathan Cohen and president Saul Rosenthal each bought 4.63 million shares at an average price of $5.40 for a total of $25 million. FTAI Aviation CEO Joseph Adams Jr. bought 59,000 shares at an average price of $82.00 for a total of $4.84 million. This reflects shares purchased in an underwritten public offering that closed Thursday. Petco Health & Wellness director Cameron Breitner bought 750,000 shares at an average price of $3.14 for a total of $2.35 million. Agree Realty director John Rakolta Jr. bought 20,000 shares at an average price of $59.32 for a total of $1.19 million. Claros Mortgage CEO Richard Mack bought 160,000 shares at an average price of $7.20 for a total of $1.15 million. Shares were down nearly 17% over the prior three months. — CNBC’s Nick Wells contributed reporting.