Trading & Options · Profile from Trading and Options Research Companion
Takashi Kotegawa (BNF)
The Japanese individual day trader, known online as "B・N・F", who began trading Japanese shares in 2000 with about ¥1.6m (~US$15,000 at ~¥108/$, approximate) and became nationally known on 8 Dec 2005, when a Mizuho Securities employee entered an order to sell 610,000 shares of J-Com at ¥1 instead of one share at ¥610,000 — 42 times the company's 14,500 shares outstanding. Kotegawa bought 7,100 shares in the minutes the price sat at its daily limit, sold 1,100 the same day, and received cash settlement for 6,000 shares (41.38% of the company), a gain of about ¥2.035bn (~US$17m) according to the large-shareholding report he filed on 16 Dec 2005 and press accounts (Japanese Wikipedia citing the filing; Settled by C17). Mizuho's loss was ~¥40.7bn, and the Tokyo Stock Exchange was ordered to pay it ¥10.7bn — a ruling made final by the Supreme Court on 3 Sep 2015 (Settled by C17). His reported assets grew to ¥15.7bn at end-2006 and ¥18.5bn at end-2007 (Diamond ZAi; Nikkan Sports, reported). He has given few interviews since 2009 and published no audited record. In this KB he is the rare documented retail success — documented in a regulatory filing and a court-tested market event — and the lesson is that his best-evidenced edge was specific, not general: fast reaction to a once-in-decades error in a market where erroneous trades were not cancelled, layered on a reported short-term mean-reversion style that has no public, testable record.
At a glance
- Name
- Takashi Kotegawa (小手川隆); online handle "B・N・F" (also written BNF; the handle's meaning is not documented in the sources checked)
- Born
- 5 Mar 1978, from Ichikawa, Chiba (zakzak, 7 Feb 2008, via Japanese Wikipedia — verify)
- Based
- Tokyo
- Type
- Individual trader; this profile has five moves because few decisions are documented (rule 6)
- Markets
- Japanese cash equities on the Tokyo Stock Exchange and other Japanese markets; no reported derivatives activity (verify)
- Starting capital
- ~¥1.6m from savings and part-time work, 2000; ¥1.64m in Oct 2000 (zakzak, 24 Jan 2008; Diamond ZAi, Oct 2007 — via Japanese Wikipedia)
- Reported assets
- ¥2.8m (end-2000); ¥61m (2001); ¥96m (2002); ¥270m (2003); ¥1.15bn (2004); ¥8bn (2005); ¥15.7bn (2006); ¥18.5bn (2007); ~¥19bn (early 2008) — the 2006–08 figures cite Diamond ZAi, Nikkan Sports and zakzak; the 2000–05 year-ends carry no specific citation (Japanese Wikipedia) — all self-reported or press-reported, unaudited
- Signature event
- J-Com, 8 Dec 2005: 7,100 shares bought; 6,000 cash-settled; ~¥2.035bn gain on those 6,000 (large-shareholding report, 16 Dec 2005, via Japanese Wikipedia)
- Reported style
- Buying sharp short-term falls — stocks well below their 25-day moving average — and selling rebounds within days (secondary sources; no first-hand rule set found; verify)
- Property
- Chomu Chomu Akihabara building ~¥9bn (Oct 2008, Nikkan Sports); AKIBA Culture ZONE ~¥17bn estimated (2011, Zai Online, 2013); Chomu Chomu sold Mar 2018 (Rakumachi) (all reported)
5 strategic moves analysed
Each one gets a full strategy file in the companion: context, the decision, the financing, what happened, and the lesson.
2000
Starting With 1 6m Yen and the Rebound Style
Founding or fund launch / new strategy
2005
J Com Fat Finger Trade
Large trade or position — event trade
2006
Scaling Into Large Caps
Leverage, sizing or risk-limit change — capacity
2008
Lehman Loss and the Akihabara Building
Loss response and diversification
2009
Going Quiet and Moving Into Property
Strategy pivot