Mueller Industries Inc (MLI) is undervalued and Proto Labs Inc (PRLB) is overvalued.
Against our estimates of intrinsic value, MLI trades at the wider discount: a margin of safety of +21%, against -299% for PRLB.
Values as of the 22 Sept 2026 close.
Discounting its cash flows at 10.3% (average of 3 methods) values the shares at $76.07; the price of $59.90 is 21% below that value, and 72% of that value comes from beyond year five.
Leak Score 100/100 on 3 of 12 signals
Discounting its cash flows at 11.4% (average of 3 methods) values the shares at $22.44; the price of $89.46 is 299% above that value, and 68% of that value comes from beyond year five.
Leak Score 0/100 on 2 of 12 signals
| Metric | MLI | PRLB |
|---|---|---|
| Verdict | Undervalued | Overvalued |
| Price | $59.90 | $89.46 |
| Intrinsic value | $76.07 | $22.44 |
| Margin of safety | +21% | -299% |
| Leak Score | 100/100 (3/12) | 0/100 (2/12) |
| Market cap | $13.2B | $2.1B |
| Revenue growth, 5 years | 11.8% | 4.2% |
| Operating margin | 21.3% | 7.3% |
| Net margin | 18.3% | 5.4% |
| Return on equity | 26.3% | 4.5% |
| Debt to equity | 0.01 | 0.00 |
| P/E | 15.6x | 71.3x |
| Forward P/E | 13.6x | 37.5x |
| P/B | 3.7x | 3.1x |
| Dividend yield | 1.1% | — |