Walmart is using the oldest trick in the book to boost its stock price

Walmart is sweetening the pot for shareholders before its annual meeting, using the oldest trick in the book.

The retailer announced on Tuesday morning that it's authorized up to $20 billion in stock buybacks over the next two years. That's a massive amount of capital to be allocated for repurchases, which are frequently used by companies to boost shares during times devoid of other positive catalysts.

Not that Walmart will need to fall back on that tactic quite yet. In Tuesday's release, the company also reaffirmed its earnings guidance for 2018, an encouraging sign given mounting pressures in an industry operating increasingly at the whim of Amazon.

More than 6,400 store closings have been announced this year, yet Walmart has emerged relatively unscathed. The same can be said about the company's stock, which is up almost 17% so far in 2017, beating the benchmark S&P 500.

Walmart also provided an early look at fiscal year 2019, forecasting sales growth of roughly 3% and saying that it also expects to add 1,000 online grocery locations during that period. It's a move not-so-discretely aimed at Amazon, which barged its way into the grocery industry earlier this year with its $13.7 acquisition of Whole Foods.

In another anti-Amazon initiative, the company also announced on Monday a new, easier process for in-store returns for merchandise purchased online. As Business Insider's Dennis Green points out, Walmart is finding new ways to leverage its substantial existing brick-and-mortar footprint to better compete with the online juggernaut.

The company has long been viewed as the old-school retailer best-positioned to fend off the looming retail apocalypse, and its actions this week have done nothing to dispel that notion.

And investors seem to like what they're seeing out of Walmart. Its stock is up 1.5% in premarket trading, after climbing nearly 2% on Monday's announcement.