This is what I’d do about the Tesco share price right now

I last wrote about supermarket chain Tesco (LSE: TSCO) in July, arguing that the valuation was too rich with the shares at 235p.

Under chief executive Dave Lewis, the firm has been turning itself around for a few years, but the job is essentially done. The big increases in earnings are behind us, I reckon, and in July I said, a firm can only go so far when it comes to squeezing efficiencies and profits out of an enterprise.

Powerful headwinds

Indeed, rather than the robust double-digit percentage advances in earnings that weve seen over the past four years, the forward predictions are for modest single-digit increases. Instead of looking for turnaround gains ahead, I think Tesco will be relying on ordinary business growth in the years to come.

But business growth is hard to achieve in the sector because of increased competition from discounting competition such as Aldi, Lidl, and others. Meanwhile, with Tescos share price near 237p today, the forward-looking earnings multiple for the trading year to February 2021 is at about 13, and the anticipated dividend yield is just below 3.8%.

That might sound fair, but I consider Tescos business to be in long-term decline and fighting against powerful headwinds. Just this month Aldi announced plans to open more than 100 news stores across the UK in the next two years, which represents a big investment in growth and a further grab for market share.

Based on past performance, I have every faith that Aldi will succeed in its expansion and that the market share it gains will be lost by the likes of Tesco, Morrisons, and Sainsburys.

Meanwhile, I think Tescos valuation hasnt yet adjusted to the reality that the companys turnaround has been completed. Considering the firms lacklustre forward growth prospects, Id want the compensation of a dividend yield above 5%.

Potential for a valuation down-rating

On top of that, I reckon the earnings multiple should reflect that Tesco operates a high-volume, low-margin, undifferentiated, commodity-style business. Indeed, the business is nothing special or unique, and is highly vulnerable to competitive forces in the sector. To me, the price-to-earnings multiple should be no higher than about 10 and probably lower than that.

So, I see huge potential for a downward re-rating of the shares, which could drag on investor returns from current levels. And in the long term, my guess is that the enterprise will decline over time rather than grow which strikes me as the wrong trend for supporting any investment.

Thats why Id avoid Tesco shares right now and probably forever. I cant see how Tesco will be capable of outperforming its index, so Id rather invest in the index itself. In this case, an FTSE 100 index tracker would have a similar dividend yield and all the benefits of diversification across many underlying shares.