What happened Shares of United Airlines Holdings (NASDAQ: UAL) traded down more than 5% on Thursday after the airline said its board has authorized it to sell more shares. It's not yet clear whether the sales will be sold, but on a down day for markets investors didn't need much of an excuse to sell. So what In a regulatory filing, United said its board has authorized it to issue up to 37 million shares "at the market." An at-the-market offering gives United and the banks it is working with a lot more flexibility over how many shares are sold and at what price, as opposed to a formalized secondary offering in which the company would sell a predetermined number of shares at a fixed price. Image source: United Airlines. The airline noted the offering is subject to a number of terms, and said "there is no assurance that [United] will proceed with any such offering." United currently has about 311.8 million shares outstanding. Now what Investors tend to dislike stock sales, at least in the near term, because by adding shares a company makes each slice of the pie a little smaller, meaning each share owned should be worth a little less. But given what United and other airlines have been through over the past year due to the pandemic, it's hard to fault the company for taking steps to maximize its flexibility. United's share price is still down over the past year, but its enterprise value, a measure of total market capitalization plus debt, is actually up 13%. With that in mind, it isn't such a bad time to sell stock if you are in need of the cash. UAL data by YCharts The airlines are healing, but a full recovery is likely to take years. We're still at a point in this recovery where it pays to have options. United's board is acting as it should by authorizing those shares. 10 stocks we like better than United Airlines HoldingsWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and United Airlines Holdings wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Lou Whiteman has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source