Not long at all. I had 6 or 7 different stocks, trying to do the right thing and be diversified, saw they were going nowhere and put everything in IBM. I was fortunate as IBM recovered rather quickly. I recently sold at 206.64 and now I remain on the sidelines waiting for an entry point at 190-195
I used to work for IBM and Warren helped me the most last with his 10 billion purchase - split adjusted I was buying IBM for about 4.50/share in 1965-1968 - we got the stock for 85% of the market price in the ESOP for IBM. Market price at the time was 300 to 400 per share - pricey for the 60's.