The implied cap rate off NAV discount is a legitimate lens, and the fact that you separated the yield from the entry cap rate is the right instinct. Those two numbers answer different questions. The yield tells you cash flow on purchase price. The implied cap rate tells you what you paid for the underlying real estate. At a 21% NAV discount with a 7.4% implied cap rate on net lease assets, you are buying real estate at a price that would be competitive in the private market, assuming the NAV holds.
That assumption is where most of the work is happening in your analysis. Net lease NAV estimates are sensitive to the discount rate used to value the lease streams and to tenant credit quality. If the consensus NAV is anchored to a cap rate environment from 12 to 18 months ago, the 21% discount may be smaller in real terms than it looks. The question I would ask before treating that spread as a signal: what discount rate did the analysts use in the NAV model, and does it reflect where net lease assets are actually trading in the private market right now?
On the convergence speed question, the risk you did not name is that the gap can stay open longer than your thesis requires. The guide content on this strategy describes the REIT-to-private-real-estate valuation gap as the longest since the early 2000s, which means historical precedent for closure exists but patience requirements are variable. A 7.4% implied cap rate is compelling entry if management is recycling capital well and the lease duration supports it, but the stock can sit at a discount to NAV indefinitely if generalist capital stays elsewhere.
The implied cap rate works as a signal when you pair it with management's demonstrated ability to surface NAV through asset sales or accretive acquisitions. If the portfolio is marked to market by actual transactions and the spread still exists, that is a harder argument against it.
What cap rate are the underlying analysts using in the NAV build, and have there been any recent portfolio transactions that either validate or challenge it?