The Tech crash around 2000 was the one that hurt me the most. I remember that Greenspan kept raising the interest rates because of the "Irrational Exuberance" and caused the Tech Bubble to burst. I had too much Tech in the portfolio. "Live and Learn" but Tech was my life at the time.
That chart did bring back memories...... I lived and worked through that crash, the bay area had the ".dot" bubble and here in the northeast we had the "optical network" bubble. Lots of hype, fast and speculative money was flying around. High tech startups would scramble for a fast IPO, get the high evaluation and a large market capitalization. This was the goal of the venture capital back then, get an idea, hype the market and go public so that they can cash out. All this without a sustainable company business plan. That crash also change the high tech landscape as far as job opportunities on both side of the coast. That said, I'm sorry that one hurts the most. As for "Live and Learn", even if one had a fund tracking the SP500, the tech crash and the credit bubble at 08 resulted in effectively 13 years of savings just going "sideways" (no growth & no loss if you ride it out). This can be explained since the SP500 index along with passive and active funds that tracks this was based on market capitalization (# of shares times price per share ). As such, is prone to Irrational Exuberance, if a company or a sector is hyped, it can draw speculative money to enlarge the market capitalization. Lots of financial/economy prof who are contemporary of Shiller were looking at the data leading up to these turbulent times. Some from the Fama/French circle who were studying factors noticed low volatility stocks or portfolios had better performance than a straight forward market cap. Below is one example of a backtest ***, instead of a portfolio weighted to the market cap of the SP500, a low volatility weight is placed to the SP500 index. What you will see is the low volatility weighting gave a smoother ride through the tech crash and thru the credit bubble recovered faster, 3 years instead of 5 years. The rationale is the low vol factor would not weigh highly the stocks where the large crowds are jumping on board due to speculation thus causing high volatility, see the VIX chart leading up to the tech crash.
As for the present, some are concern about FANG (Facebook,Apple Netflix and Google) these are the tech giants holding up the SP500, again through their market cap. If one or some of these giants suddenly fall so goes the index. I'm a firm believer this risk can be mitigated by using indices other than market cap. See the Morningstar link of SPHD, go to the portfolios section, it has no FANG yet performs as well and better when dividends are included. Also, I purposely allocated my funds where the majority of FANG are in my IRA and 401K so that I can switch over to bonds with no tax consequences.
*** disclaimer, past performance is no guarantee of future results...... but it could lead to high likelihood.