Question: We would appreciate your help in determining the best time to send funds to buy extra shares in a company-sponsored dividend reinvestment plan. We can't seem to get good answers from the company or the bank agents--maybe because we're not asking the right question. What we want to know is the latest date we can send funds for stock purchase to earn the next declared dividend, so that the money doesn't lie dormant for any length of time.

Answer: The optional purchase plans offered by many corporations as a part of their automatic dividend reinvestment plans provide an opportunity to buy fractional shares of corporate stock without brokerage fees.

Because such purchases are usually made in small amounts, timing is not particularly significant. But if you consider it important, the secret is in having your funds arrive at the purchasing office as close as possible to the dividend record date.

Ownership of the shares on the record date is required to qualify for the next dividend. Generally the record date is from 30 to 45 days before the payment date--and that's a lag you can't eliminate.

Some corporations only purchase shares for participants once a month or once a quarter, on a date not necessarily related to the dividend date.

For example, Boston Edison Co.--whose prospectus happens to be handy as I write--says: "Optional cash payments . . . will be invested quarterly on the first business day in March, June, September and December."

In such a case you would want to have your check arrive as close to the specified purchase date as you can safely manage. But keep in mind the uncertainties of mail service and intra-office communications.

Best suggestion I can make: Read the prospectus for your company's dividend reinvestment plan. It will tell you the policy on investing optional cash payments. If funds are invested on receipt, check your quarterly dividend reinvestment statements for guides to the record dates.

Q: I recently lost my job and was forced to cash in some U.S. savings bonds. The bank only gave me a figure showing interest earned. I was told no Form 1099 would be issued. What happens to these bonds after they are turned in? Does the Treasury Department send a 1099 to the IRS showing interest paid to the individual? If not, it seems to me a lot of interest would go unreported.

A: The bank that cashed your Series E bonds was right; they are only required to tell you how much of the total redemption amount represents earned (and taxable) interest. There is no Form 1099-INT issued.

But the Bureau of the Public Debt (a part of the Treasury Department) does notify the Internal Revenue Service (another part of Treasury) of all bond redemptions along with the amount of taxable interest.

For many years Series E bonds were issued by name only; since 1973, however, Social Security numbers have been required also on all bond purchases. And recently banks and other redemption agencies started getting Social Security numbers on redemption as well.

So the machinery is in place for the IRS to computer-match interest on redeemed Series E and EE bonds, much as they match dividends and other interest payments against individual tax returns.

On May 31 I gave you the names of a couple of brokers you could write for a list of utility stocks with dividend reinvestment programs that qualify for tax deferral.

Now you can add to that list Johnston, Lemon & Co., well-known local brokers. Contact any of their offices or write to Johnston, Lemon & Co., Attn: Raleigh E. Kraft, Atrium Building, Alexandria, Va., 22314.