Stock prices drop by the same amount as their dividend payment the day after it is paid. This is done intentionally to prevent schemes like the one you suggest. Your strategy will result in a zero-sum gross gain.
However, after you factor in the hidden transaction costs from selling your mutual fund shares and then buying them back, as well as the transaction costs of buying and selling your company's stock, you will then be in the minus. And, if the company's shares lose value in the mean time, you lose even more. Congrads, you just made the brokers very rich while you got poorer.
When it comes to retirement investing, you need to think long term. This sort of quick turnaround tactic will only get you in trouble and distract you from your long-term goals. Costs are a vital factor in determining your overall wealth.
Consider this exerpt from chapter 19 of my free book (downloadable at
http://www.invest-for-retirement.com)
Let's follow the results of three different large-cap stock funds over a period of 40 years. I will assume that each fund earns a gross return - the return of the stocks themselves - of 8% each year, on average. As our discussion in previous chapters has shown, over long periods of time the gross returns on funds of the same type tend to be very similar because the market is efficient. Fund A has a 2% expense ratio, Fund B has a 1.3% expense ratio, and Fund C has a 0.1% expense ratio. For simplicity, we will not factor in loads, taxes, or indirect costs. Therefore, the net return to the investor would be the gross return minus the expenses. For Fund A, the net return would be 8 minus 2, or 6%. For Fund B, the net return would be 8 minus 1.3, or 6.7%. For Fund C, the net return would be 8 minus 0.1, or 7.9%.
The following chart shows the account balance of each fund over a period of 40 years. In this example we start with a $10,000 lump-sum investment and make no further contributions. The dividends and capital gains are reinvested, so the return is compounded. Here are the results.
Fund Final Value at 40 Years
A $102,857
B $133,837
C $209,343
Notice the low-cost fund wound up with twice the final value as the high-cost fund. Small differences in costs compound to very large differences in final wealth. I can demonstrate examples of how for every 0.5% increase in annual expenses, you will fall short by $100,000 or more over a period of 30+ years. And, for people maxing out their 401(k) plans, over a period of 40 years, for every 0.5% increase in annual expenses, you will fall short by a quarter of a million dollars.