Some companies report this combined figure on the face of the balance sheet, tagged CashCashEquivalentsAndShortTermInvestments in XBRL. Others report cash and short-term investments on separate lines, and the total is calculated by adding them; the investments line is tagged ShortTermInvestments. The split between the two depends on maturity when purchased: a three-month rule of thumb, drawn from ASC 230, separates cash equivalents from short-term investments.
Regulation S-X Rule 5-02.1 covers cash and requires restricted amounts to be disclosed separately. Rule 5-02.2 covers current marketable securities; it defers to GAAP for equity securities and, for other securities, requires the company to state the basis on which the balance is carried along with the alternative of cost or market value. Debt securities are measured under ASC 320 at fair value or amortized cost depending on classification, so the reported figure may not equal what the portfolio would fetch if sold today.
Analysts use this total when judging how much of a company's value sits in liquid financial assets and how well it can absorb losses or repay debt without borrowing. It is a common alternative to cash alone when calculating net debt or a cash-rich company's enterprise value. Keep in mind that long-term investment portfolios, often large at technology and insurance companies, are excluded, and that some of the balance may be held abroad or reserved for operating needs.