Bernstein points out Buffett's rule for buying tech stocks: Sell when the P/E ratio exceeds 30!
For Apple, Buffett has shown a clear sensitivity to valuation,establishing most of his positions when the P/E ratio is below 15, selectively adding at a P/E ratio of 20 or below, and reducing positions when the P/E exceeds 30.Last quarter, Apple's average P/E ratio was 30.