The markets are clearly of two minds about the Primerica Corporation, the financial conglomerate that owns Smith Barney, Harris Upham & Company, the Commercial Credit Company and the A. L. Williams insurance operation.

The stock market, to judge by the drubbing the company's shares have taken in the past two months, thinks that Primerica is a poor bet, in part because of emerging problems at the A. L. Williams unit. The bond market's opinion, expressed last week when Commercial Credit sold $100 million in three-year notes, is that Commercial Credit - the bedrock on which Primerica is built - is only slightly less creditworthy than Uncle Sam himself. The odds are, the bond market goofed. The corporate bond market typically classifies borrowers by how much more they pay to borrow than the United States Treasury pays. The gap is measured in basis points, or hundredths of a percentage point. Thus, traders speak of a bond as being priced to yield, say, 150 basis points over Treasuries - that is, 1.5 percentage points more than the Treasury bond yield for the same maturity. Of course, if the borrower offers some sort of collateral, its borrowing costs are likely to be closer to the Treasury rates than if it does not.

Last Monday, the day the Commercial Credit notes were priced, Norwest Bank sold an issue of three-year secured notes, carrying a glittering triple-A by both Moody's and Standard & Poor's. Norwest's interest rate was 75 basis points over Treasury's.

Commercial Credit has a single-A rating from Standard & Poor's. As for collateral, it offered nothing but its good name.

Firoz Tarapore, assistant treasurer of both Primerica and Commercial Credit, said the company was the beneficiary of ''fortunate timing,'' selling the notes early in the week, before unrest in the Middle East caused spreads in the bond market to widen. As for the rate, he deemed it to be ''right in with the pack'' of similar issues.

Myron Picoult, an analyst with Oppenheimer & Company, may not be an expert on corporate bond spreads but he has made a thorough study of Primerica for his stock-market clients. On the question of whether one should invest in the company these days, his advice is succinct: don't.

''The stock has clearly broken down, and investor confidence has been shaken,'' he said. ''We would continue to avoid the stock and believe that there is still some downside risk.''

⇒  One thing that worries Mr. Picoult is the unfolding drama at Williams, which Primerica purchased in 1988 from its controversial founder and self-styled ''coach,'' Art Williams. For years, Mr. Williams's aggressive selling style has made him a hero to his 190,000 agents and a thorn in the flesh of his industry rivals. After the Primerica buyout, he stayed on as a sales consultant and de facto leader of the insurance operation, which produces almost a quarter of Primerica's profits.

⇒ Primerica's fans among Wall Street analysts say the A. L. Williams issue is an ''aberration'' and ''an irrelevancy.'' But Mr. Picoult points out that Primerica's promising plan to use Mr. Williams's aggressive disciples to sell the products and services of other subsidiaries, including Commercial Credit, could be derailed by the current turmoil.

⇒ Moreover, he said, ''one wonders whether the United States Attorney's investigation could lead to review of the A. L. Williams operation in other jurisdictions by various state insurance departments, given past complaints about the company.''

Commercial Credit's own market niche is hardly worry-free these days. Of its $4.7 billion portfolio of loans, about 45 percent is secured by real estate - not as much of a comfort as it was before real estate prices started to soften.

Another 45 percent of its portfolio consists of unsecured loans to consumers. And how's that business? Andrew Silver, a senior analyst and economist at Moody's Investors Service, warned in a report last week that the borrowing binge of the 1980's has seriously eroded the consumer's creditworthiness.

But, possibilities aside, it is certain that Commercial Credit is in the business of lending money to real estate buyers and consumers. It is equally certain that the nation's real estate sector is ailing and it is becoming harder for consumers to pay their debts.

All of which suggests a final possibility: That when bond market investors take a closer look at how little they are being paid to lend money to the Commercial Credit unit of Primerica, a lot of them will wish they had listened to the stock market.