Kevin Mahn, chief investment officer at Hennion and Walsh, says that stock market valuations have again risen to where they should make investors nervous, based on where they stand compared to price/earnings ratios for the market. As a result, Mahn says investors will need to be more selective for the rest of this year and all the way through 2022. Mahn is turning to preferred securities for the income side of portfolios, and looking in biotech, e-commerce and technology for stocks, favoring small- and mid-cap issues which he says are better values.