There were cases like that in the pre-Bork era (i.e. when the courts interpreted the law as people who originally wrote it actually intended). Here's one example:
"In 1955, the date of this merger, Brown was the fourth largest manufacturer in the shoe industry, with sales of approximately 26 million pairs of shoes and assets of over $72,000,000 while Kinney had sales of about 8 million pairs of shoes and assets of about $18,000,000."
And even more relevant:
"Another important factor to consider is the trend toward concentration in the industry. It is true, of course, that the statute prohibits a given merger only if the effect of that merger may be substantially to lessen competition. But the very wording of § 7 requires a prognosis of the probable future effect of the merger.
The existence of a trend toward vertical integration, which the District Court found, is well substantiated by the record. Moreover, the court found a tendency of the acquiring manufacturers to become increasingly important sources of supply for their acquired outlets. The necessary corollary of these trends is the foreclosure of independent manufacturers from markets otherwise open to them. And because these trends are not the product of accident, but are rather the result of deliberate policies of Brown and other leading shoe manufacturers, account must be taken of these facts in order to predict the probable future consequences of this merger. It is against this background of continuing concentration that the present merger must be viewed."
https://supreme.justia.com/cases/federal/us/370/294/
"In 1955, the date of this merger, Brown was the fourth largest manufacturer in the shoe industry, with sales of approximately 26 million pairs of shoes and assets of over $72,000,000 while Kinney had sales of about 8 million pairs of shoes and assets of about $18,000,000."
And even more relevant:
"Another important factor to consider is the trend toward concentration in the industry. It is true, of course, that the statute prohibits a given merger only if the effect of that merger may be substantially to lessen competition. But the very wording of § 7 requires a prognosis of the probable future effect of the merger.
The existence of a trend toward vertical integration, which the District Court found, is well substantiated by the record. Moreover, the court found a tendency of the acquiring manufacturers to become increasingly important sources of supply for their acquired outlets. The necessary corollary of these trends is the foreclosure of independent manufacturers from markets otherwise open to them. And because these trends are not the product of accident, but are rather the result of deliberate policies of Brown and other leading shoe manufacturers, account must be taken of these facts in order to predict the probable future consequences of this merger. It is against this background of continuing concentration that the present merger must be viewed."