diff --git a/crates/pptx/src/write.rs b/crates/pptx/src/write.rs
index e4c0858c9..2a5a2115b 100644
--- a/crates/pptx/src/write.rs
+++ b/crates/pptx/src/write.rs
@@ -794,11 +794,11 @@ fn master_xml(x: &mut Exp, o: &mut Out, m: &Master, layouts: &[(u64, String)]) -
     }
     w.close("p:sldLayoutIdLst");
     w.open0("p:txStyles");
-    let (dt, db, dother) = defaults::master_styles();
-    let pick = |s: &deckcraft_model::text::ListStyle, d: deckcraft_model::text::ListStyle| if s.is_empty() { d } else { s.clone() };
-    dml::list_style(&mut w, x, o, "p:titleStyle", &pick(&m.title_style, dt));
-    dml::list_style(&mut w, x, o, "p:bodyStyle", &pick(&m.body_style, db));
-    dml::list_style(&mut w, x, o, "p:otherStyle", &pick(&m.other_style, dother));
+    // An imported empty body style has no bullets; saving must not author defaults into it.
+    // New decks already carry their populated master styles in the model.
+    dml::list_style(&mut w, x, o, "p:titleStyle", &m.title_style);
+    dml::list_style(&mut w, x, o, "p:bodyStyle", &m.body_style);
+    dml::list_style(&mut w, x, o, "p:otherStyle", &m.other_style);
     w.close("p:txStyles");
     ext_list(&mut w, ext_children(m.raw_ext.as_deref()).as_deref());
     w.close("p:sldMaster");
diff --git a/crates/pptx/tests/it/main.rs b/crates/pptx/tests/it/main.rs
index ddbca4ee9..6c136a37d 100644
--- a/crates/pptx/tests/it/main.rs
+++ b/crates/pptx/tests/it/main.rs
@@ -14,6 +14,7 @@ mod fills;
 mod kept_parts;
 mod locks;
 mod malformed;
+mod master_text_styles;
 mod math_ns;
 mod media_timing;
 mod notes;
diff --git a/crates/pptx/tests/it/master_text_styles.rs b/crates/pptx/tests/it/master_text_styles.rs
new file mode 100644
index 000000000..a539a1dc0
--- /dev/null
+++ b/crates/pptx/tests/it/master_text_styles.rs
@@ -0,0 +1,110 @@
+//! Imported empty master styles must not become the defaults used to author new decks.
+use std::io::{Cursor, Read, Write};
+use std::sync::Arc;
+
+use deckcraft_geom::Xfrm;
+use deckcraft_model::resolve::{self, Ctx};
+use deckcraft_model::text::{Align, Bullet, ParaProps, TextBody};
+use deckcraft_model::{PhType, Placeholder, Presentation, Shape, ShapeId, defaults};
+
+fn subtitle(text: &str) -> Shape {
+    let mut body = TextBody::from_text(text);
+    body.paragraphs[0].props.align = Some(Align::Center);
+    Shape {
+        id: ShapeId(102),
+        name: "Centered subtitle".into(),
+        ph: Some(Placeholder { kind: PhType::SubTitle, idx: 1, ..Default::default() }),
+        xfrm: Some(Xfrm::new(120.0, 120.0, 720.0, 90.0)),
+        text: Some(body),
+        ..Default::default()
+    }
+}
+
+/// Author an input with empty title/other styles and the specified body style, without asking
+/// the serializer under test to supply its own master text styles in the input.
+fn imported(body_style: &str) -> Presentation {
+    let mut p = defaults::new_presentation(None);
+    let m = Arc::make_mut(&mut p.masters[0]);
+    m.shapes.clear();
+    for l in &mut m.layouts {
+        l.shapes = vec![subtitle("")];
+    }
+    Arc::make_mut(&mut p.slides[0]).shapes = vec![subtitle("Centered subtitle")];
+    let bytes = deckcraft_pptx::export(&p).expect("base package");
+    let mut z = zip::ZipArchive::new(Cursor::new(bytes)).expect("zip");
+    let mut out = zip::ZipWriter::new(Cursor::new(Vec::new()));
+    for i in 0..z.len() {
+        let mut part = z.by_index(i).expect("part");
+        let name = part.name().to_string();
+        let mut data = Vec::new();
+        part.read_to_end(&mut data).expect("read");
+        if name.starts_with("ppt/slideMasters/slideMaster") && name.ends_with(".xml") {
+            let mut xml = String::from_utf8(data).expect("generated XML");
+            let start = xml.find("<p:txStyles>").expect("styles start");
+            let end = xml.find("</p:txStyles>").expect("styles end") + "</p:txStyles>".len();
+            xml.replace_range(start..end, &format!("<p:txStyles><p:titleStyle/><p:bodyStyle>{body_style}</p:bodyStyle><p:otherStyle/></p:txStyles>"));
+            data = xml.into_bytes();
+        }
+        out.start_file(name, zip::write::SimpleFileOptions::default()).expect("start");
+        out.write_all(&data).expect("write");
+    }
+    deckcraft_pptx::import(&out.finish().expect("finish").into_inner()).expect("import fixture")
+}
+
+fn resolved_subtitle(p: &Presentation) -> ParaProps {
+    let slide = &p.slides[0];
+    let shape = slide.shapes.iter().find(|s| s.name == "Centered subtitle").expect("subtitle");
+    assert_eq!(shape.ph_type(), Some(PhType::SubTitle));
+    assert_eq!(shape.xfrm, Some(Xfrm::new(120.0, 120.0, 720.0, 90.0)));
+    let text = shape.text.as_ref().expect("text");
+    assert_eq!(text.text(), "Centered subtitle");
+    resolve::para(&Ctx::for_slide(p, slide).expect("context"), shape, &text.paragraphs[0])
+}
+
+fn saved(p: &Presentation) -> Presentation {
+    deckcraft_pptx::import(&deckcraft_pptx::export(p).expect("export")).expect("reopen")
+}
+
+#[test]
+fn an_imported_empty_master_keeps_its_unbulleted_subtitle_after_two_saves() {
+    let mut p = imported("");
+    let before = resolved_subtitle(&p);
+    assert_eq!(before.bullet, None);
+    assert_eq!(before.align, Some(Align::Center));
+    for _ in 0..2 {
+        p = saved(&p);
+        assert_eq!(resolved_subtitle(&p).bullet, None, "saving must not add a subtitle bullet");
+        let master = &p.masters[0];
+        assert!(master.title_style.is_empty(), "do not invent an imported title style");
+        assert!(master.body_style.is_empty(), "do not invent bullets in an imported body style");
+        assert!(master.other_style.is_empty(), "do not invent an imported other-text style");
+        assert_eq!(resolved_subtitle(&p), before);
+    }
+}
+
+#[test]
+fn an_explicit_unbulleted_body_style_keeps_its_properties() {
+    let mut p = imported(r#"<a:lvl1pPr><a:buNone/><a:defRPr sz="1900"><a:latin typeface="Carlito"/></a:defRPr></a:lvl1pPr>"#);
+    let expected = p.masters[0].body_style.clone();
+    assert_eq!(resolved_subtitle(&p).bullet, Some(Bullet::None));
+    for _ in 0..2 {
+        p = saved(&p);
+        assert_eq!(p.masters[0].body_style, expected);
+        assert_eq!(resolved_subtitle(&p).bullet, Some(Bullet::None));
+    }
+}
+
+#[test]
+fn newly_authored_presentations_keep_their_populated_master_defaults() {
+    let mut p = defaults::new_presentation(None);
+    let m = &p.masters[0];
+    let expected = (m.title_style.clone(), m.body_style.clone(), m.other_style.clone());
+    assert!(!expected.0.is_empty() && !expected.1.is_empty() && !expected.2.is_empty());
+    assert_eq!(expected.1.levels.len(), 9);
+    assert!(matches!(expected.1.level(0).expect("body level").para.bullet, Some(Bullet::Char { .. })));
+    for _ in 0..2 {
+        p = saved(&p);
+        let m = &p.masters[0];
+        assert_eq!((&m.title_style, &m.body_style, &m.other_style), (&expected.0, &expected.1, &expected.2));
+    }
+}