Diversifying a Value Portfolio
Even Benjamin Graham insisted that net-nets should be bought as a diversified portfolio, not as individual stock picks. The statistical edge comes from spreading your capital across 10-20 positions and letting the averages work in your favour.
Position Sizing
Conservative approach: No single position larger than 5% of your portfolio. For a £10,000 portfolio, that means £500 per stock across 20 holdings.
Concentrated approach: 10% per position across 10 high-conviction stocks. More volatile but higher potential returns if your analysis is correct.
Correlation Matters
Diversification only works if your holdings are not all correlated. Owning 10 UK bank stocks is not diversification — if one falls due to a banking crisis, they all fall. Spread across different sectors, geographies (UK + US), and company sizes.
When to Sell
Graham's original net-net approach had a simple sell rule: hold for 12 months or until the stock reaches its NCAV, whichever comes first. Modern practitioners often use a 2-year holding period. The key is having a rule and sticking to it, rather than making emotional decisions.