International non-public fairness and infrastructure funding supervisor 3i Group (LSE: IIII) is essentially the most profitable FTSE 100 inventory in my self-invested private pension (SIPP).

It’s one of many first shares I purchased after taking cost of three legacy firm pensions final summer season. I invested £2k in August, October and November. At the moment my stake is value virtually £10k, together with reinvested dividends. Over 12 months, the 3i Group share price is up virtually 65%. 

This isn’t a flash within the pan. It’s up 193% over 5 years. Solely Frasers Group (269%) and Diploma (197%) have carried out higher. I’m thrilled however now I’m questioning whether or not to take the cash and run. Or reasonably, reinvest it.

3i Group is a winner however…

I see myself as a long-term buy-and-hold investor. Promoting goes towards the grain. It makes even much less sense once I think about 3i Group’s stellar monitor file, which dates again to 1945. It floated in 1994 and now manages belongings value greater than £22bn.

3i is an funding belief and a rarity, in that it trades at a premium to its the underlying web worth of the belongings it holds. After the volatility of current years, many trusts commerce at a 30% low cost or extra, nevertheless it’s at a whopping 43.96% premium.

That’s an indication of success, clearly. In 2024, web asset worth per share rose virtually 20% to 2,085p, regardless of a 33p per share international change loss.

Its non-public fairness enterprise delivered a 25% gross funding return of £4.059bn, albeit down on the earlier yr’s 40% improve. Now right here’s my concern. That return was largely pushed by the efficiency of its largest holding by far, Dutch low cost retailer Motion Group.

3i took a forty five% fairness stake in 2011 for a mere £134m. At the moment, Motion is Europe’s fastest-growing non-food low cost retailer with greater than 2,300 shops and €8bn of annual revenues. 2024 was one other very sturdy yr as 3i pocketed worth progress of £3.61bn, dividends of £375m and an extra £762m through a pro-rata share redemption.

Promote my winner

Motion’s storming success offset softer efficiency from different portfolio holdings, that are “working through adverse phases of their market cycles”. 3i’s infrastructure enterprise additionally floundered. It appears to be like like a one-trick pony.

It doesn’t wish to let go of Motion. In actual fact, it elevated its fairness stake from 54.8% to 57.6% within the newest first quarter. And why not? Q1 earnings rose one other 23% to €843m, though 9% gross sales progress was down from 22% yr on yr. It’s nonetheless rolling out shops however inevitably at a slower tempo.

Motion is now 72% of 3i’s total non-public fairness portfolio. I’m making an costly play on a single European low cost retailer whose progress will inevitably gradual.

Additionally, the place’s the exit technique? Non-public fairness firms have struggled to search out consumers amid financial uncertainty and better rates of interest. 3i has carried out a superb job with Motion. Which will proceed for some time however the ceiling is looming. I’m planning to promote half my stake earlier than it hits it. I can’t bear to let go of all of it, although. I owe it some loyalty.