Securities and Exchange Commission members will now be allowed to accept travel and hotel expenses from securities industry trade groups when they attend the groups' conferences and meetings. They cannot, however, accept speaking fees.

That makes the SEC one of a handful of government agencies whose officials are permitted by law to accept such payments, according to David Martin, director of the Office of Government Ethics in the Office of Personnel Management. Martin said he believes that some Commerce, State and Health and Human Services employes are permitted by law to accept such payments.

Other agencies' employes may also be permitted to do so by their agency's code of conduct. However, he was not sure whether the employes of any other regulatory agency were allowed to accept the payments.

A recently enacted change in the Securities Act permits the SEC chairman to approve the payments for both commissioners and staff. Prior to the change, commissioners' expenses had to be picked up by the SEC, unless the organization were tax-exempt. If staff members took leave to attend the meetings, they could accept payments from nonprofit and educational groups, subject to the chairman's approval.

According to SEC officials, Chairman John S.R. Shad requested the change about a year and a half ago to enable agency officials to continue to attend the meetings in the face of the budget squeeze. The commissioners spent $19,000 in fiscal 1981 on travel and $15,000 last year, according to agency figures.

In order to eliminate conflicts of interest--or appearances of them--the SEC drafted detailed regulations. SEC officials will not be able to accept reimbursement from any entity it regulates. However, the chairman will decide whether the SEC will be reimbursed by "an association predominantly composed of entities regulated by the commission."

In other words, said SEC ethics counsel Myrna Siegel, officials couldn't accept payments from Merrill Lynch, but they might be able to accept them from the Securities Industry Association, whose members are the brokers and dealers regulated by the SEC. TIMELY PROXY MATERIAL . . . Starting Nov. 1, brokers will be required to send proxy material to their clients within five business days after they receive it from corporations. The current rule says only that the material must be passed on "promptly." And, as of Jan. 1, the names of stockholders whose shares are held by their brokers will be revealed to the corporations unless the customers object. Corporations have complained that they are unable to get pertinent materials to stockholders in time for them to act on tender offers or other opportunities. MISSING STOCK . . . The dollar value of lost, missing, stolen or counterfeit securities certificates climbed 15 percent last year to just over $1 billion.

However, thanks to a tracing program set up by the SEC, $20.6 million of those certificates were located, or 27 percent more than in the previous year.

The data base is operated by Securities Information Center in Wellesley Hills, Mass. Since its establishment in 1977, it has logged more than $5 billion worth of lost, stolen or counterfeit securities. ODDS AND ENDS . . . The SEC and the North American Securities Administrators Association are launching an effort to bring uniformity to overlapping, duplicative and even contradictory state and federal regulations governing securities sales. A hearing will take place in Washington Sept. 12 to discuss problems and possible solutions . . . . Lee B. Spencer Jr., director of the SEC's Corporation Finance Division, plans to resign next month to return to private law practice.