ST. LOUIS — Completion of the spin-off of Post Holding, Inc.’s 80.1% interest in BellRing Brands, Inc. in mid-March helped drive an earnings gain at the St. Louis-based company in what otherwise was a quarter in which the company’s chief executive said the business “is not firing on all cylinders” and “still earning below our potential.”

Net income at Post in the second quarter ended March 31 was $523.3 million, equal to $8.47 per share on the common stock, up sharply from $109.9 million, or $1.71 per share, in the same period a year ago. The most recent quarter included a $447.7 million gain on the company’s investment in BellRing.

Net sales increased 17% to $1.41 billion, up from $1.2 billion in the same period a year ago.

“We are pleased with Post’s performance this quarter,” Robert V. Vitale, president and chief executive officer, said during a May 6 conference all with analysts. “Nonetheless, the business is not firing on all cylinders, and we are still earning below our potential. The expected second half increase reinforces that thesis. Meanwhile, labor conditions are improving. Controllable manufacturing performance is improving. Transportation is improving. I make the distinction about controllable manufacturing because we continue to face sporadic ingredient shortages that create inefficiencies in our factories and in our broader supply chains.

“Our procurement team has developed a triage approach to identifying flash points at the earliest possible moment, starting with better demand planning. However, because it is triage, it does lead to downstream inefficiencies. I expect the supply chains to continue to improve, and our management of shortages will continue to improve. But the combination of pandemic disruption, labor imbalance, inflation and now geopolitical instability has led to more lingering macro problem than we anticipated. Speaking of inflation, we have seen rampant cost increases across our business. For the most part, we have been able to raise prices to offset the cost increases, but the timing varies across our segments.”

Segment profit within the company’s Post Consumer Brands business fell 13% in the first quarter, easing to $79.5 million from $91.8 million. Net sales increased 19% to $573.1 million from $479.9 million.

“Post Consumer Brands had a solid performance,” Mr. Vitale said. “Again, it was not perfect as we manage both supply interruptions and the resulting inefficiencies. We have reversed distribution losses in our key Malt-O-Meal franchise with expanded distribution available in stores in April. And at the same time, we are continuing to see a modest shift toward value price consumption.”

Volumes in the Post Consumer Brands business increased 20% in the quarter, reflecting strength within the Pebbles and Honey Bunches of Oats brands, said Jeff A. Zadoks, chief financial officer. He added that growth was partially offset by year-over-year softness across value and private label cereal products and the exit of certain low-margin business.

Segment profit within the Weetabix business rose to $26.8 million, up 3.4% from $25.9 million in the same period a year ago. Net sales moved up 3.2% to $117 million from $113.4 million.

“Weetabix continues to navigate challenging waters exceptionally well,” Mr. Vitale said. “UK and European consumers are more directly feeling the impact of Ukraine-related disruption reflected in higher energy and food prices. Meanwhile, we will face a currency headwind as the pound has weakened against the dollar.”

Foodservice profit totaled $20 million in the quarter, up 127% from $8.8 million a year ago. Net sales increased 22% to $451.9 million from $369.2 million.

Segment profit in the Refrigerated Retail business was lower in the quarter, falling 30% to $17 million from $24.2 million. Net sales increased to $267.6 million from $239.5 million.

“Our Refrigerated Retail platform is improving nicely,” Mr. Vitale said. “Our side dish business resumed growth as capacity recovered. We are approaching the level of capacity at which we can resume our brand-building efforts. On the other hand, we have struggled with commodity volatility in both our cheese and sausage categories.”

Mr. Vitale said the recent acquisitions of Henningsen, the TreeHouse Foods private label cereal business and Egg Beaters are exceeding expectations, while the Peter Pan business is meeting expectations with the likelihood that synergies will begin to hit that business’s P&L in 2023. Meanwhile, Almark is underperforming expectations, he said, noting that costs have escalated faster than the company had priced.

Net income in the six months ended March 31 totaled $502.5 million, or $8.16 per share, up from $191.1 million, or $2.94 per share, in the same period a year ago. Net sales totaled $2.75 billion, up from $2.38 billion.