Cathie Wood is the founder, CEO, and CIO of ARK Investment Management. Elon Musk is the CEO of Tesla.Ark Invest, File (for Wood) and Hannibal Hanschke/Pool Photo via AP, File (for Musk).Ark Invest is buying Tesla stock for the first time in eight months, according to its daily trade report.Cathie Wood's flagship fund purchased about $30 million of Tesla stock on Thursday after a 12% post-earnings decline.Tesla remains Ark Invest's top holdings across its funds, but Teledoc is in a close second place.Sign up here for our daily newsletter, 10 Things Before the Opening Bell.Cathie Wood's Ark Invest bought Tesla stock for the first time in eight months on Thursday, according to its daily trade report.Ark Invest purchased 27,799 shares of Tesla in its flagship ARKK ETF, and purchased another 5,683 shares in its ARKW Next Generation Internet ETF.