A poor prospectus and jittery investors dropped two stocks, while an overseas deal and solid earnings boosted two other firms’ shares this week.

Calabasas-based casual dinning chain Cheesecake Factory Inc. was stung by downgrades after analysts forecast soft business for the rest of the year. The stock lost 13 percent to $37.62 for the week.

Wall Street investors dropped Mankind Corp. lost 12 percent over concerns that the company’s inhalable insulin treatment could have trouble winning approval from the Food and Drug Administration. Shares in the Valencia-based biotech firm closed the week at $12.60.

On the up side, Enova Systems Inc. received a boost from a deal it signed to produce drive-train parts for a British electric car manufacturer. Shares in the Torrance-based company gained 16 percent to $7.20.

Ameron International also gained, after reporting strong second quarter earnings. Shares in the Pasadena-based industrial pipe maker rose 9 percent to $92.84 for the week.