Many government organizations and additional types of nonprofit institutions will be able to earn interest on checking accounts at savings and loan institutions under a regulation approved yesterday by the Federal Home Loan Bank Board. The agency also requested public comment on whether partnerships should be allowed to open the interest-bearing, or negotiable order of withdrawal (NOW), accounts as well.

In another proposal designed to aid hard-pressed thrift institutions, the board devised a special accounting method whereby thrifts can sell low-yielding mortgage loans without showing losses on their balance sheets.

Besides individuals, those eligible for NOW accounts include businesses operated as sole proprietorships, unincorporated businesses owned by married couples (so-called Mom-and-Pop operations), nonprofit organizations and government units.

The Federal Reserve had decreed this week that only tax-exempt nonprofit organizations could set up NOW accounts at banks. But the bank board expanded the eligibility so that nonexempt organizations such as political action committees, and state and municipal funds also are eligible to earn interest on checking accounts at savings and loans.

The Fed also limited eligibility of government organizations for NOW accounts to funds used for schools, colleges, universities, libraries or hospitals. Finding that limit "unduly restrictive," the bank board opened up NOW accounts to all government and quasi-government entitites except those making a profit. Examples of the latter incude Federal Home Loan Banks and the Federal Home Loan Mortgage Corp., which buys mortgages on the secondary market.

However, a bank board attorney said that because S&Ls cannot lend money to some government entities, those entities might not want to deposit funds in S&Ls.

Finally, the board is seeking public opinion on whether profit-making partnerships should be eligible. It asks whether those considered as "organizations" should be barred, as distinct from those considered a "collection of individual partners," which would be allowed. The Fed makes no mention of partnerships in its eligibility requirements.

In a potentially more controversial ruling, the bank board yesterday proposed to suspend generally accepted accounting principles and regulatory accounting principles in favor of optional-deferral accounting. By using optional-deferral accounting, savings and loans could sell low-yielding mortgage loans or Government National Mortgage Association securities without having to show a loss at the time of sale. Instead, the loss would be deducted over the remaining life of the mortgage or security.

The change would not remove any of 360 or more thrifts from the bank board's list of financially troubled institutions because it would not improve their earnings, according to a bank board staff member. However, it would enable them to cash in their old assets without penalty and thus free funds for higher-yielding mortgages or investments. Mortgages worth about $80 billion now are estimated to be yielding less than current market rates.

Under optional-deferral accounting, for example, a thrift could sell an 8 percent mortgage with a face value of $100,000 and a market value of $60,000 and use the proceeds to issue a new mortgage at 16 percent. Instead of a $40,000 loss, the loan would be carried on the books as a $100,000 asset.