I've been analyzing infrastructure stocks with de-facto monopoly positions over the past weeks to have them as stable, dividend-paying anchors in my portfolio. I looked at airports, electricity grids, midstream, railways, toll roads, and water utilities. Findings: ✈️ Airports: I invested in Fraport. The stock stood out due to its relatively low valuation compared with other listed airport operators, while the company is coming out of a multi-year investment cycle. With capex expected to decline over the coming years, I see potential for higher free cash flow and eventually stronger dividends. ASUR was a close second, combining a strong position around Cancún Airport with additional exposure to airports in Mexico, Puerto Rico and Colombia. ⚡️ Electricity Grids: I decided to invest in Terna, Italy's national electricity transmission operator. I particularly liked the combination of a long-term uptrending chart, a roughly 4% dividend yield, predictable regulated earnings and continued investment into Italy's power grid. National Grid was a close second, offering a similar infrastructure moat through its electricity networks in the UK and US. ⛽️ Midstream: I currently own ONEOK, which operates a large network of pipelines, processing facilities and storage infrastructure across the US. I liked the combination of a reasonable earnings multiple, close to a 5% dividend yield and a long-term chart that had already broken above major resistance and successfully retested it. Enterprise Products Partners was a close second, with an equally attractive valuation and dividend profile. 🚆 Railways: I haven't made an investment yet, but have been closely monitoring the chart of Central Japan Railway for a potential entry, as it seemed undervalued from an earnings standpoint relative to other railway companies. Most other railway stocks I looked at were trading at relatively high earnings multiples and/or unattractive positions in their long-term charts. 🚗 Toll Roads: Not a pure toll-road play, but I bought into VINCI, as its diversification across several infrastructure sectors seemed like a good long-term investment. Its toll-road concessions generate a significant share of group profits, while airports, energy infrastructure and construction provide additional diversification. 🚿 Water Utilities: The only sector where I didn't find a company that combined a relatively low earnings multiple, an attractive entry point and a high dividend yield. There were a few interesting candidates, particularly in the UK, but none stood out enough for me to add the sector to my portfolio at current prices.