Shares of Apple (NASDAQ:AAPL) enjoyed solid gains today, rising more than $15, or nearly 4%, by the afternoon following four days of relentless selling that saw the Mac maker shed nearly $29 since last Tuesday. That four-day streak of losses put the company down over 6%, representing a market cap decline of an incredible $27 billion.

Apple's valuation fell below the important threshold of $400 billion in the process, with yesterday's low of $419 valuing the company at $393 billion. Shares have now reclaimed that threshold. What drove the rally?

Talking heads
Two Street analysts appeared on CNBC this morning to discuss Apple's prospects, which may have fed some bulls.

BGC Financial analyst Collin Gillis, who rates Apple a hold, acknowledged that it would seem that the stock is starting to bottom out. Gillis feels confident that investors will see some news out very soon regarding its cash balance and the inevitable dividend boost.

The analyst also points out that every time investors have tried to call the bottom thus far, they've been cut while trying to catch a falling knife since shares simply keep dropping. If Apple were to increase its dividend to closer to a 4% yield, Gillis sees shares responding. He was a bit surprised by the rally that Apple saw last year when it reinitiated its dividend in the first place.

Bernstein Research analyst Toni Sacconaghi, who considers Apple a buy and has assigned a $725 price target, was expectedly more bullish than Gillis. Investors widely believe that Apple is preparing to "materially" return more cash, a move that Sacconaghi believes could spark a rally of $40 to $50. Without this type of catalyst, shares could potentially be modestly higher or lower by the time the Mac maker's April earnings release rolls around.

Sacconaghi also goes as far as to say that the June estimates are too high, and investors are now focusing heavily on Apple's new method of providing guidance since Apple's forecasts are no longer expected to be comically low. The company's outlook could prove to weigh on shares, absent any other positive catalysts such as a dividend increase.

Overall, the analyst still believes Apple is "very inexpensively valued and an exceptional value for long-term investors," but it still has some perception challenges with growth investors. This class of investors still needs to see some product catalysts, such as a major carrier partnership or a new device, to be satiated.

Maybe there's a simpler explanation
Perhaps the analyst chatter is helping boost shares today. Perhaps it's just a rebound rally, plain and simple.

On the way down over the past six months, Apple has posted several intense rebound rallies that proved to be nothing more than temporary reprieves. Investors may remember when shares surged a whopping 7% on a single day in November on no specific news. That rebound allowed Apple to reclaim the $500 billion market cap threshold, only to surrender it shortly thereafter.

Fellow Fool Eric Bleeker, CFA, crunched the numbers and found that the 7% rally even ranked as its 20th largest daily gain in 10 years. All of it for no fundamental reason; bears merely needed to take a breather. Today's 3% jump is similarly encouraging -- even if it's just a sign of selling pressure is exhausted.

Come on in
With Apple now valued at just over $400 billion and its cash representing a third of that total, shares are unarguably "very inexpensively valued" by almost any metric investors can think of. Apple's P/E is just under 10, far cheaper than the broader S&P 500 at 17.5. Even though you'd think its bargain metrics would already be tempting value investors, just wait until they pile in after the inevitable dividend boost.