diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e96c04a5d4a..099ba311f489 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,7 +22,7 @@
 
 ### Performance
 
-- `[jest-core]` Cache micromatch in SearchSource globsToMatcher and avoid recreating RegExp instances in regexToMatcher ([#10131](https://github.com/facebook/jest/pull/10131))
+- `[jest-core, jest-transform]` Improve Jest startup time and test runtime, particularly when running with coverage, by caching micromatch and avoiding recreating RegExp instances ([#10131](https://github.com/facebook/jest/pull/10131))
 
 ## 26.0.1
 
diff --git a/packages/jest-transform/src/shouldInstrument.ts b/packages/jest-transform/src/shouldInstrument.ts
index d9fcdcd268c3..bd71314076de 100644
--- a/packages/jest-transform/src/shouldInstrument.ts
+++ b/packages/jest-transform/src/shouldInstrument.ts
@@ -8,7 +8,7 @@
 import * as path from 'path';
 import type {Config} from '@jest/types';
 import {escapePathForRegex} from 'jest-regex-util';
-import {replacePathSepForGlob} from 'jest-util';
+import {globsToMatcher, replacePathSepForGlob} from 'jest-util';
 import micromatch = require('micromatch');
 import type {ShouldInstrumentOptions} from './types';
 
@@ -16,6 +16,20 @@ const MOCKS_PATTERN = new RegExp(
   escapePathForRegex(path.sep + '__mocks__' + path.sep),
 );
 
+const cachedRegexes = new Map();
+const getRegex = (regexStr: string) => {
+  if (!cachedRegexes.has(regexStr)) {
+    cachedRegexes.set(regexStr, new RegExp(regexStr));
+  }
+
+  const regex = cachedRegexes.get(regexStr);
+
+  // prevent stateful regexes from breaking, just in case
+  regex.lastIndex = 0;
+
+  return regex;
+};
+
 export default function shouldInstrument(
   filename: Config.Path,
   options: ShouldInstrumentOptions,
@@ -33,15 +47,15 @@ export default function shouldInstrument(
   }
 
   if (
-    !config.testPathIgnorePatterns.some(pattern => !!filename.match(pattern))
+    !config.testPathIgnorePatterns.some(pattern =>
+      getRegex(pattern).test(filename),
+    )
   ) {
     if (config.testRegex.some(regex => new RegExp(regex).test(filename))) {
       return false;
     }
 
-    if (
-      micromatch([replacePathSepForGlob(filename)], config.testMatch).length
-    ) {
+    if (globsToMatcher(config.testMatch)(replacePathSepForGlob(filename))) {
       return false;
     }
   }
@@ -59,10 +73,9 @@ export default function shouldInstrument(
     // still cover if `only` is specified
     !options.collectCoverageOnlyFrom &&
     options.collectCoverageFrom.length &&
-    micromatch(
-      [replacePathSepForGlob(path.relative(config.rootDir, filename))],
-      options.collectCoverageFrom,
-    ).length === 0
+    !globsToMatcher(options.collectCoverageFrom)(
+      replacePathSepForGlob(path.relative(config.rootDir, filename)),
+    )
   ) {
     return false;
   }