The core business is shrinking, and acquisitions aren't paying off quickly enough. Source: Post Holdings. 

Since being spun out of Ralcorp in 2012, packaged foods purveyor Post Holdings (NYSE:POST) has gone from an exciting opportunity to invest in a company run by a living legend in Bill Stiritz to one that's underperformed at every turn, created billions of debt, and now faces questions about its path forward with major -- unexpected -- leadership changes announced in early October. 

With the fourth-quarter's earnings release expected any day, what should investors expect? Let's take a closer look at where things stand. 

Stiritz's acquisitions yet to lead to market-beating results
Stiritz was profiled in the book The Outsiders and lauded for his execution while running Ralston-Purina. His record at the company, which included producing better than 20% annualized returns for almost two decades, is the stuff of legends.

When it was announced that he would be leading Post Holdings when it was spun out of privately held Ralcorp a few years back, the investor community was more than a little excited by the prospects. However, things haven't exactly gone as planned since taking Post Holdings public. 

Stiritz made it clear from the beginning that he and his management team would aggressively invest in improving and expanding Post Holdings, but the results so far can best be described as mixed. A big driver of this has been a steady consumer shift away from traditional breakfast cereals, which has led to a steady decline in Post's core business. 

This is a big reason Stiritz and his team have spent more than $3 billion in acquisitions since taking the company public, but it has also been one of the drivers behind the company reducing its guidance each of the past three quarters.

Last quarter, the company reported a loss of $0.90 per share, well short of the expected $0.21 profit analysts were expecting. The results sent the stock down 15%, and it is down 40% from the high in March as of this writing. 

Leadership changes muddy the water, but probably not as much as you think
Though he is 79, it came as a real shock when it was announced in October that Stiritz would be stepping down as CEO, transitioning to the role of executive chairman, and that then-CFO Rob Vitale had been named CEO, effective Nov. 1.. Partly helped some by an analyst upgrade at Goldman Sachs, the market has responded favorably to the management shakeup, with shares up more than 14% since the announcement. 

However, it's important to understand two things regarding the changes in leadership. First, Vitale and Stiritz have worked together for decades, so any expectations that Vitale's leadership is likely to be a major departure from that of Stiritz should probably go out the window. Second, only time will tell if this is a good or a bad thing, because the process of acquisition and integration that Post Holdings' leadership is following is likely to take years to play out.  

Iterative progress is more important than this (or next) quarter's results 
Analyst earnings estimates are $0.07 EPS for the quarter, but the range is anywhere from a penny per share up to $0.12, and with only a handful of analysts covering the company, the results could fall in a wide range of potential outcomes.

However, that's really not what matters at this stage of the game, because today's Post Holdings -- as much as it has already been rebuilt in less than three years -- is probably not the company shareholders will own in another few years, as management continues to acquire new brands and potentially divest underperforming assets.

Probably the two most important things investors should look for in each earnings call going forward is some indication that the acquisitions -- and the steps to integrate these acquisitions into the business -- are generating adequate and sustainable returns. 

So far, it hasn't worked out exactly to plan, and investors have suffered. But in all fairness, only a few quarters' results probably isn't enough time to adequately measure the results of what management is doing. This is likely one of the biggest drivers behind Stiritz' transition to more of a "big-picture" role, and Vitale's ascent to CEO.

Will the newly repositioned leadership team and realigned corporate structure lead to faster -- and better -- results? Only time will tell. Either way, it's probably going to remain a bumpy ride.