Kan småsparare slå marknaden?
36 professorer svarar på två frågor om småsparare, indexfonder och enskilda aktier
Vad säger finansvärldens främsta akademiker om småsparares chanser att slå marknaden? Här är resultaten från en stor undersökning där över 30 professorer svarade på de två frågorna: ”Kan småsparare förutsäga hur priset på en aktie kommer utvecklas?” och ”Bör småsparare förvänta sig bäst avkastning från en bred, billig och passiv indexfond eller ett fåtal enskilda aktier?”.
Innehållsförteckning
- Sammanfattning, guldkorn och citat
- Därför är detta avsnitt viktigt
- Krossande resultat för aktieselektering
- Varför det är omöjligt att slå marknaden
- Indexfonder vinner stort
- Diversifiering - den enda gratis lunchen
- Varför din hjärna lurar dig
- Jack Bogle får rätt igen
- Kontrovers: Går det aldrig att slå marknaden?
- Vad betyder detta för dig?
- Sanningen om marknadseffektivitet
- Tidshorisontens betydelse
- Viktiga nyanser att komma ihåg
- Fråga 1. Kan småsparare förutsäga hur aktier kommer att gå?
- Fråga 2. bättre att äga en indexfond än ett fåtal enskilda aktier?
- Vanliga frågor
- Communityns tankar, tips och inspel
- Relaterade sidor och annat kul
- Senaste nytt på RikaTillsammans
Denna sida uppdaterades 3 månader sedan (2025-07-28) av Jan Bolmeson.
Sammanfattning och guldkorn
Det viktigaste att veta. Swipa för att se fler.
Fråga 1. Kan småsparare förutsäga hur aktier kommer att gå?
Sammanställning av de olika professorerna svar:
| Efternamn | Förnamn | Fråga 1. | Konfidens | Kommentar. |
|---|---|---|---|---|
| Campbell | John | Strongly Agree | 10 | This is certainly true for liquid stocks, although for certain illiquid stocks ”bid-ask bounce” can generate predictable daily movements (but one cannot profit from these). |
| Cochrane | John | Strongly Agree | 10 | If the average investor (weighted by wealth) could predict the stock to rise, the stock would go up right away. Half of the predictions must be wrong. |
| Cornelli | Francesca | Did Not Answer | ||
| Diamond | Douglas | Strongly Agree | 8 | |
| Du | Wenxin | Strongly Agree | 8 | |
| Duffie | Darrell | Strongly Agree | 9 | Market clearing generally implies that the price reflects commonly available information. |
| Eberly | Janice | Strongly Agree | 9 | |
| Fama | Eugene | Strongly Agree | 10 | |
| Gabaix | Xavier | Agree | 8 | |
| Goldstein | Itay | Strongly Agree | 8 | |
| Graham | John | Strongly Agree | 9 | |
| Harvey | Campbell | Agree | 9 | |
| Hong | Harrison | Strongly Agree | 6 | |
| Jiang | Wei | Agree | 8 | |
| Kaplan | Steven | Strongly Agree | 10 | |
| Kashyap | Anil | Strongly Agree | 10 | Everyone should have to read Ken French’s Presidential Address to the American Finance Association on the perils of active investing. |
| Koijen | Ralph | Did Not Answer | ||
| Kuhnen | Camelia | Strongly Agree | 10 | |
| Lo | Andrew | Strongly Agree | 10 | The competition in this endeavor, just among the top 10 investment banks, is intense, not to mention the hedge-fund industry, so retail investors don’t have a chance. |
| Lowry | Michelle | Strongly Agree | 8 | |
| Ludvigson | Sydney | No Opinion | ||
| Maggiori | Matteo | Did Not Answer | ||
| Matvos | Gregor | Strongly Agree | 9 | |
| Moskowitz | Tobias | Strongly Agree | 10 | Forecasting daily returns is extremely difficult since daily price changes are dominated by news and noise, which are both unpredictable. |
| Nagel | Stefan | Strongly Agree | 9 | |
| Parker | Jonathan | Strongly Agree | 9 | There is some predictability in a stock’s return at longer horizons, but a retail investor cannot consistently predict stock movements day to day. The vast majority of day to day stock price movements are unpredictable even to experts with proprietary information. |
| Parlour | Christine | Agree | 8 | |
| Philippon | Thomas | Strongly Agree | 9 | |
| Puri | Manju | Strongly Agree | 9 | |
| Roberts | Michael | Strongly Agree | 9 | |
| Sapienza | Paola | Agree | 10 | |
| Seru | Amit | Strongly Agree | 7 | |
| Stambaugh | Robert | Strongly Agree | 10 | |
| Starks | Laura | Agree | 5 | |
| Stein | Jeremy | Strongly Agree | 9 | |
| Stroebel | Johannes | Agree | 10 | |
| Titman | Sheridan | Agree | 9 | |
| Van Nieuwerburgh | Stijn | Strongly Agree | 8 | ample empirical evidence that retail investors systematically underperform |
| Whited | Toni | Strongly Agree | 1 | |
Fråga 2. bättre att äga en indexfond än ett fåtal enskilda aktier?
Sammanställning av de olika professorerna svar:
| Efternamn | Förnamn | Fråga 2 | Konfidens. | Kommentar |
|---|---|---|---|---|
| Campbell | John | Strongly Agree | 10 | With equal expected returns, diversification reduces risk and is one of the few ”free lunches” in economics. And typical retail investors can’t increase their expected returns through stock-picking. They may benefit from factor exposure but that remains diversified. |
| Cochrane | John | Strongly Agree | 10 | Again, the average investor theorem proves this must be true on average. |
| Cornelli | Francesca | Did Not Answer | ||
| Diamond | Douglas | Strongly Agree | 10 | |
| Du | Wenxin | Strongly Agree | 8 | |
| Duffie | Darrell | Strongly Agree | 9 | From my response to the first question (prices reflect information), for a given return volatility, mean portfolio returns are improved less by stock selection than by levered diversified positions. (Bill Sharpe) |
| Eberly | Janice | Strongly Agree | 9 | |
| Fama | Eugene | No Opinion | Do better is too vague. | |
| Gabaix | Xavier | Strongly Agree | 9 | |
| Goldstein | Itay | Agree | 8 | |
| Graham | John | Strongly Agree | 9 | |
| Harvey | Campbell | Agree | 7 | The question is what does ”do better” mean? The investor might have lottery-like preferences leading to an undiversified portfolio. |
| Hong | Harrison | Agree | 7 | |
| Jiang | Wei | Agree | 8 | |
| Kaplan | Steven | Strongly Agree | 10 | |
| Kashyap | Anil | Strongly Agree | 7 | Great advice for almost everyone. We should all thank Jack Bogle |
| Koijen | Ralph | Did Not Answer | ||
| Kuhnen | Camelia | Strongly Agree | 10 | |
| Lo | Andrew | Strongly Agree | 10 | The historical data are pretty clear on this point, especially over investment periods longer than a few years. Obviously, within shorter samples, anything can happen. |
| Lowry | Michelle | Strongly Agree | 8 | |
| Ludvigson | Sydney | Agree | 8 | |
| Maggiori | Matteo | Did Not Answer | ||
| Matvos | Gregor | Strongly Agree | 9 | |
| Moskowitz | Tobias | Strongly Agree | 10 | I’m assuming by ”better” we mean on a risk-adjusted basis or for cumulative wealth. Holding a well-diversified portfolio at the same expected return is better for accumulating wealth over long horizons. A single stock with the same return and much higher vol. is worse. |
| Nagel | Stefan | Strongly Agree | 9 | |
| Parker | Jonathan | Strongly Agree | 10 | |
| Parlour | Christine | Agree | 8 | |
| Philippon | Thomas | Strongly Agree | 9 | |
| Puri | Manju | Strongly Agree | 9 | |
| Roberts | Michael | Strongly Agree | 9 | |
| Sapienza | Paola | Agree | 10 | |
| Seru | Amit | Strongly Agree | 7 | |
| Stambaugh | Robert | Strongly Agree | 9 | |
| Starks | Laura | Agree | 5 | |
| Stein | Jeremy | Strongly Agree | 9 | |
| Stroebel | Johannes | Strongly Agree | 10 | |
| Titman | Sheridan | Agree | 9 | |
| Van Nieuwerburgh | Stijn | Strongly Agree | 9 | |
| Whited | Toni | Strongly Agree | 1 |
