The rental car giant's shares are reliving a bit of their 2021 glory today. But recent troubles don't inspire confidence in the rally. Shares of Hertz Global Holdings (HTZ 11.76%) were moving higher on Monday amid a revival of investor interest in the so-called meme stocks that surged earlier this decade.As of 11:30 a.m. ET, Hertz's shares were up about 12.3% from Friday's closing price.A former meme stock gets another day in the sunMany former meme stocks -- led by GameStop -- were trading sharply higher o ...