Many businesses have supply chains. If you print books, you may have a supplier for ink, paper, glue and printers. A guitar maker probably has suppliers for wood, strings, frets, bridges, etc.
Now what if you are your suppliers? You make the frets, the bridges, the paper, the ink… TIL that they'll call you vertically integrated. Although technically they say "the combination of 2 or more stages of production normally operated by separate companies."1
Tomato tomato. ↩